For the first half of the season, it seemed as if Clay Buchholz might never find a way into the Red Sox rotation. Now, he is a pitcher whom the Red Sox cannot do without.

The second-half saga of the Sox rotation took more twists on Saturday. Tim Wakefield, a few days removed from a dazzling start in his return from the D.L., experienced a recurrence of the discomfort in his lower back that had sidelined him until Wednesday. Paul Byrd, who was sitting on his couch hoping a big-league club might call less than four weeks ago, will make his big-league return on Sunday. In a procedural move, the Sox optioned Junichi Tazawa to the Rookie Level Gulf Coast League, though he will likely make another start on Friday or Saturday in Chicago.

It was, to be sure, a busy day for the Red Sox to plot a course with their rotation. The net effect of the developments was to reinforce a shortcoming that has been evident since the All-Star break: the Red Sox are struggling to find stability among their starters beyond Josh Beckett and Jon Lester.

Yet in the wake of that unwanted reminder, the Sox received a glimmer of promise that the situation may not be dire. That is because Buchholz delivered one of the finest outings of his career in leading the Sox to a 3-2 victory over the Blue Jays at Fenway. (Recap.)

The right-hander pitched into the ninth inning, leaving the game just two outs short of a complete-game shutout. Though the inherited runner he left on base scored, his line accurately reflected a night of total dominance: 8.1 innings, three hits, one run, two walks, nine strikeouts.

It was just the second time that Buchholz had ever pitched into the ninth (the other coming in his no-hitter in Sept. 2007). He punched out nine, matching a career-high, and showed an array of swing-and-miss pitches, his success chiefly the byproduct of a precise low- to mid-90s fastball and a devastating change made better by the effectiveness of his heater.

He also added the occasional slider and curveball, the latter producing the most memorable pitch of the night in the first inning, when Jose Bautista ducked away from what he feared was a pitch aimed at his head that instead swept back over the inside corner. Buchholz seemed confident and purposeful with everything he threw, something that the pitcher says reflects the progress of his game over the roughly two years since he announced himself to the baseball world with a no-hitter on Sept. 1, 2007.

“When I got up here and I was new to the big leagues, (catcher Jason Varitek) put down a sign and I just grabbed it and threw it. That’s where I got in trouble,” said Buchholz. “Now I think I’ve evolved into a pitcher instead of just being able to go out there and throw a ball.”

The 25-year-old was ruthlessly efficient on Saturday, needing just 107 pitches (67 strikes). Buchholz threw first-pitch strikes to 24 of the 29 batters (83 percent) he faced.

“He was throwing a lot of 0-1, 0-2 counts. When you face a pitcher like that who jumps on you early in the count, it’s pretty tough,” said catcher Victor Martinez. “It’s not a secret. Clay has great stuff…As a hitter, I don’t really want to face him. I’m glad on his side now.”

He got 16 swings and misses on the night: 12 on changeups (eight of those coming from the seventh inning on), two on sliders, and one each on a fastball and curve. Buchholz had a complete arsenal, and he and Martinez knew how to employ it to unbalance the Jays.  

The performance was impressive enough in its own right, but in the larger context of Buchholz’ recent performances, the outing continued an important trend. In his last five outings, Buchholz has delivered four quality starts, working to a 3.38 ERA in that time and, increasingly, giving his team reason to expect that it can compete and have a chance to win when he takes the mound.

With Wakefield’s status uncertain, the emergence of another reliable pitcher in the rotation is critical for the Sox down the stretch. Increasingly, Buchholz looks capable of being that pitcher.

“We have a lot of important games to play,” said Sox manager Terry Francona. “He’s probably not always going to go eight and change, but he looked like a pretty good major-league pitcher.”

Buchholz entered spring training this year with a snaking line of pitchers in front of him in his attempt to earn a spot in the Sox rotation. He stood behind Beckett, Lester, Wakefield, Daisuke Matsuzaka, Brady Penny, John Smoltz and perhaps even Justin Masterson and Michael Bowden ahead of him.

Now, the group has been redefined. And on the cusp of September, Buchholz looks not only like a pitcher whose spot in the rotation is secure, but one who will play a huge role in determining his team's fate in September and potentially October.

Here are four other lessons from Saturday:

BEHIND BUCHHOLZ, QUESTIONS LOOM

Wakefield’s situation seemed ominous. The 43-year-old moved gingerly through the Sox clubhouse, just three days removed from a night that had been singularly triumphant.

Given that he missed more than a month after injuring his back after the All-Star break, the Sox were understandably concerned that a source of potential rotation stability may not be available to them.

“There has to be some concern because he’s miserable,” said Francona.

Pitching coach John Farrell said that the team did not have a timetable for the knuckleballer’s return to the rotation. Wakefield will be examined more extensively on Monday. The manager suggested that the All-Star might get an epidural at that time in hopes of calming the affected area.

Even if/when Wakefield does return, given the recurrence of the injury, it would appear that the team cannot simply rely on the notion that Wakefield will remain healthy for the rest of the year.

As a reflection of that notion, the Sox shifted their rotation. The team scratched 38-year-old Paul Byrd from his start in Pawtucket on Saturday so that he can make his return to the majors on Sunday.

Byrd has pitched himself into shape quickly after spending most of the year at home. Since signing with the Sox in early August, he has pitched in four minor-league games, most recently allowing one run on three hits in seven innings for Pawtucket on Aug. 24.

“He feels good about himself,” said Francona. “He feels like he’s found his changeup. That gives him confidence. I haven’t seen him pitch…But we know what we’ll get. He won’t run away from competition. And more often than not, he’ll give you a good chance to win a game.”

Still, given the amount of downtime that he had, it would be difficult to know what kind of results to anticipate from the veteran. The same can be said of 23-year-old Tazawa, who was optioned to the GCL after allowing nine runs in four innings on Thursday.

The demotion was purely procedural. Ordinarily, a player must remain in the minors at least 10 days after he is optioned, but since the GCL season ends on Monday, Tazawa can be recalled on Tuesday. Francona said that the rookie will start on either Friday or Saturday in Chicago.

Yet he, too, represents something of an unknown. Given the questions around Wakefield, Tazawa and Byrd, the efforts of Daisuke Matsuzaka to return to the majors take on all the more urgency.

Earlier in the week, G.M. Theo Epstein said that Matsuzaka was not being viewed by the organization as a savior. He has been out since June, following consistently poor performances following the year.

Nonetheless, the right-hander – who will pitch for Double A Portland on Sunday as his next step in a progression intended to have him back in the majors by Sept. 8 – clearly has an opportunity to offer an important contribution to his club.

“He’s done a great job with the time he was in Florida. It’s very easy to see with the naked eye that he’s reshaped himself,” said Farrell. “Most importantly, he dedicated himself to that time down there knowing there was some time left here and still the opportunity to get back and pitch at the major-league level.

“With the next few starts, we’ll get a better, more accurate read on that. At this point, any contributions he gives us, we’ll certainly take. At some point, we’re going to need that.”

ELLSBURY CAN’T OUT-RUN THE DOUBLE PLAY           

One of the more exciting elements of watching the Red Sox is the opportunity to see burner Jacoby Ellsbury motor around the bases. The single-season record holder for stolen bases by a Red Sox (55 and counting) made life interesting in the bottom of the eighth.

He blasted a ball towards the triangle, just to the left of the Red Sox bullpen. The ball bounced up the centerfield wall, with visions of a potential inside-the-park homer looming as Ellsbury downshifted while rounding second.

Ellsbury was held, but as is often the case, the Red Sox leadoff hitter offered a moment of breathless excitement.

“Every time you see a guy like Jake just flying around the bases, it’s a lot of fun,” said Martinez.

Given that speed, one would imagine that with a bases-loaded situation and one out, Ellsbury would seem like exactly the kind of batter whom a team would like at the plate. He makes contact, having struck out just once every 54 times at the plate, and the combination of his speed and left-handedness would appear to make him one of baseball’s tougher player to double-up.

Yet when Ellsbury stepped to the plate with the bases packed and one out in the bottom of the second, he swung at Ricky Romero’s first-pitch 94 mph fastball and grounded it to short for a relatively easy 6-4-3 double play.

Interestingly, Ellsbury has been one of the most frequent victims of double play balls on the Red Sox, having grounded into a dozen twin killings thus far this year. Among the Sox, Ellsbury ranks behind only Mike Lowell (19) and Dustin Pedroia (17) in double-play balls, a fairly surprising development given that he leads the majors with 55 steals.

While the pairing of great speed and double play balls is surprising, it is not unprecedented. Since 1979, there are 146 instances of players stealing 50 or more bags in a single season; of those, 30 have grounded into at least 10 double plays, and 15 (not including Ellsbury) have hit into a dozen or more, including a couple (Luis Polonia in 1992 and Jerry Mumphrey in 1980).

Since 1901, the record for the most double play balls by a player to steal at least 50 bases is 19. The two players with that record are Cesar Cedeno in 1973…and Hall of Famer and former all-time stolen base leader Lou Brock, who grounded into 19 double plays and swiped 56 bags in 1976.

WAGNER COULD HAVE BEEN A RED SOX CLOSER

Billy Wagner was not brought to Boston to be a closer…this time.

Since joining the Sox on Thursday, the left-hander has sat idly in the bullpen while watching Jonathan Papelbon put the finishing touches on a pair of victories. Wagner, in his ongoing recovery from Tommy John surgery, is expected to serve as part of the setup crew in front of Papelbon, rather than the man to whom the middle relief innings flow.

But that doesn’t mean that the idea of having Wagner as a game-ending presence hasn’t occurred to the Sox. Wagner was last a free agent following the 2005 season, following three years with the Phillies. The Sox’ ninth-inning was somewhat unsettled, since Keith Foulke was coming off of a season that had been mostly lost to injuries, and Mike Timlin – despite a serviceable couple of months as a fill-in closer – was not viewed as ideally suited for the role.

And so the Sox talked with Wagner’s representatives in general terms about the possibility of bringing the left-hander to Boston to stabilize the ninth. Wagner was intrigued by the Red Sox, but the conversations never advanced beyond the preliminary stages, since the Mets blew away not only any other potential offer, but also Wagner’s expectations.

Wagner said that he was hunting for a three-year, $30 million deal following the 2005 season, and that he imagined that at the end of that deal, he would be ready to retire. But the Mets, according to the pitcher, blew him away by saying they were willing to go as many to as five years.

The deal ended up being a guaranteed four-year, $43 million agreement with an option that could increase its value to as much as $50 million over five years. Such an offer was beyond what the Sox – or any other team – was willing to contemplate, and so Wagner ended up with the Mets.

The Sox emerged from spring training with Keith Foulke as their closer, but in the season’s third game, they summoned Papelbon to blow away the Rangers in the ninth inning for his first career save.

Papelbon has since added 144 more saves for the Sox, and is now the unquestioned ninth-inning force for the Sox. Wagner, who saved 101 games for the Mets before blowing out his elbow towards the end of last year, now joins him in Boston in a role that is quite different from the one that he and the Sox discussed nearly four years earlier.

A TOP PROSPECT ENDURED A SETBACK

As the Providence Journal first reported on Saturday, outfielder Ryan Westmoreland suffered a broken clavicle while running into a wall while making a spectacular running catch for Single A Lowell on Friday night. Westmoreland, considered one of the top prospects in the Sox system, is done for the year.

The outfielder is scheduled to undergo surgery to insert a plate and screws to stabilize the clavicle on Tuesday, according to Sox farm director Mike Hazen. He will miss the remainder of Lowell’s season, and will also be unable to play during the Fall Instructional League. He will be ready to commence a normal offseason strength and conditioning program by late-November or early December.

Westmoreland injured himself in just his eighth game in the outfield after spending most of the season as a DH for the Spinners while recovering from January surgery to repair a torn labrum. The 19-year-old was enjoying a spectacular season in which he was hitting .296 with a .401 OBP and .885 OPS, meriting a spot on the New York-Penn League All-Star team.

The Sox are hopeful that Westmoreland’s latest injury will not dim what had seemed a very bright future.

“It’s still way too early to determine any long-term impact, although doctors are very optimistic that it will not have (a) negative impact,” Hazen wrote in an email.

Westmoreland, a fifth-round pick in the 2008 draft, signed with the Sox out of Portsmouth (RI) High School for a $2 million bonus last summer.