Brad Penny was remarkably consistent while putting together a solid half season body of work in Boston prior to the All-Star break, and headed into Saturday’s start with a stretch of six straight outings during which he’d allowed three runs or less.

Penny was among the AL’s top 10 starters with a 2.67 ERA since June 11. But the 31-year-old is now fighting against a personal trend that’s repeated itself since the 2005 baseball season. The big burly righty is effective and strong during the first half of the baseball season, but his stuff – and, by proxy, his statistics and effectiveness – take a pronounced dip in the second half of the year. 

Saturday afternoon’s subpar mound effort by Penny in a 6-2 loss to the Toronto Blue Jays represents only one start, of course, and there won’t be any drastic measures taken after one defeat. In fact, the big righty was the first Sox starter in eight games to give up more than three runs in an appearance. Penny had the normal upper register of velocity on his fastball, and was grunting and gunning his way to 95-96 mph heaters against a Jays lineup leading all of Major League Baseball in hits this season.

The 6-foot-4, 240-pounder made it through five innings and gave up six runs on eight hits – the most damage he’s sustained on the mound since dropping a 5-1 game to the Texas Rangers back on June 5.

The Jays had a sound game plan against Penny on Saturday afternoon, however, and fought off his most searing fastballs while instead attacking the hard-throwing right-hander’s breaking and off-speed stuff.

Four of the eight hits surrendered by Penny – including a big two-run Jose Bautista double in the fourth inning – came when he shied away from the overpowering fastball and instead served a curve or change up in a hitter’s happy zone.

Despite it only being one isolated outing, a legitimate question worth asking is if the Sox are about to see the same Penny that’s struggled in many of his post-All-Star break outings over the last five seasons. Here are the numbers that are worth repeating: Penny’s pre-All-Star game starts since 2005 have seen him put up a 30-17 record in 407 2/3 innings with a 3.51 ERA (159 earned runs allowed) that helped him get selected to a pair of All-Star game appearances as a member of the Los Angeles Dodgers.

Penny’s post-All-Star break numbers aren’t quite so encouraging: a 15-14 record in 259 1/3 innings with a 5.00 ERA and a more than 30 point jump in terms of batting average against over the season’s final two plus months.

The X-factor in all of this is the diligence and solid work ethic exhibited by Penny that Sox manager Terry Francona has lauded through the first few months of the season, and his adherence to Red Sox trainer Mike Reinold’s shoulder-strengthening program. Both factors were expected to help Penny strike back against the trend that’s dogged him over his last handful of seasons, but his latest outing isn’t going to do anything to dissuade those that believe Penny just made his first small step into a much larger second half fade.

Making things even more urgent is 24-year-old Clay Buchholz’s Friday night effort in which he had the very same Blue Jays hitters baffled with his dazzling changeup and fastball command. The young righty made a strong statement that he’s ready for the Boston gig should Penny continue to exhibit some of the second-half danger signs that he’s shown over the course of his big league career.

The Sox have been lauded for their starting rotational depth through the first half of the season, and they may just need it if recurring patterns of the Penny’s recent past hold true to form.

Here are four other things that I learned in Saturday’s 6-2 loss to the Toronto Blue Jays:

JED LOWRIE MIGHT JUST BE READY TO END THAT SHORTSTOP CAROUSEL

The 25-year-old switch-hitting shortstop didn’t really get a chance to show off what he’ll be able to do from the left side of the plate with a healthy wrist, but Jed Lowrie looked increasingly comfortable as Saturday’s game unfolded at the Rogers Centre. The infielder fanned on three pitches in his first at bat against rookie lefty Marc Rzepczynski, but made solid contact in his next two at bats – including a screaming rocket shot over the left field wall in the seventh inning off lefty reliever Jeff Carlson for Lowrie’s first home run of the season.

Lowrie ended the day with a 1-for-4 performance at the plate, and perhaps showed some rustiness in the field when he converged with Mike Lowell on a pop-up that the veteran third baseman was camped under in the bottom of the eighth inning. Lowrie may have had the better angle on the ball as he charged over from his shortstop position, but the ball instead glanced off Lowell’s glove amid the confusion and saddled the sure-handed shortstop with his first career error at the shortstop position after 55 career big league games at the position.

Sox manager Terry Francona is obviously going to ladle out plenty of balanced playing time to both Lowrie and Nick Green in the early going after Green truly saved the team with his steady – and oft-times spectacular – performance at the shortstop position during the first half. It’s expected that Lowrie will eventually end up capturing the majority of playing time down the stretch, but there may be plenty of innings and ABs to go around given Francona’s desire to rest Mike Lowell – and insert Lowrie at third base -- as he’s scheduled to do in Sunday afternoon’s series finale vs. Toronto.

The Sox will get a good chance to see Lowrie take some swings from the left-handed side of the plate on Sunday when prized trade target Roy Halladay takes the mound for the Blue Jays.

THE SOX OFFENSE CONTINUES TO STRUGGLE AGAINST UNFAMILIAR HURLERS

The veteran Sox offense has showed a predictable pattern of struggle against rookie pitchers – particularly left-handed rookie hurlers – that they’ve never previously faced, and that scenario once again played itself out on Saturday afternoon defeat at the hands of rookie southpaw Marc Rzepczynski.

He now joins with other young household names like Braden, Kawakami, Zimmerman, Hanson and Anderson that have been nothing short of lion-tamers against the vaunted Red Sox lineup this season.

The left-handed Rzepczynski was hitting spots with a fastball that barely cracked 90-mph along with a slider and curveball repertoire, and earned his first Major League win while helping the Jays snap a three-game losing streak in the process. He walked four and gave up four hits in six innings of work, but only let up one run while vastly outpitching Penny.

With so many veteran hitters that rely on scouting reports and video to prepare for each and every pitcher that they face during a 162 game baseball regular season, it seems nothing short of elementary Baseball 101 that the Sox wouldn’t fare well against an unknown commodity from the minor leagues – and that once again played out in Saturday’s loss to a spell-checkers nightmare in Rzepczynski.

JASON VARITEK WILL BE GETTING A BIT MORE REST IN THE SECOND HALF

If Sox manager Terry Francona’s usage of George Kottaras to catch Brad Penny on Saturday afternoon is any indication of second-half strategy, then the Sox skipper appears eager to give 37-year-old Jason Varitek a bit more proper rest in the second half of the season. Varitek was on pace to catch close to 135 games if he kept up his pre-All-Star break pace, and that’s a high number that the Sox coaching staff appears determined to avoid.

It’s been well-documented that Varitek's batting average slumps down to a .231 level over the second half of his last three seasons combined, and perhaps a little more Kottaras usage behind the plate will allow the Sox Captain to avoid a similar drop this season. The return of Varitek’s power numbers have been a pleasant surprise this season, and could be preserved with enough built-in down time.

Kottaras had a crucial passed ball in the fourth inning when he couldn’t come away with a high, hard Penny heater over his head – a ball that caught the heel of his catcher’s mitt and then bounced away – and the native Canadian didn’t have much of a happy homecoming to his home city of Toronto with an 0-for-2 performance at the plate.

Varitek pinch hit for Kottaras in the top of the ninth inning and grounded out to third to end the game, but was saved an immeasurable amount of wear and tear on his catching body by skipping a day game after night game on the Rogers Centre turf. Kottaras is scheduled to also catch Tim Wakefield during the road trip finale against Texas on Wednesday night.

THE ALL-STAR BREAK DID A BODY GOOD FOR MASTERSON AND RAM-RAM

Ramon Ramirez and Justin Masterson were among several relievers that stumbled into the All-Star break with a string of shaky performances during the month of July, and those two in particular combined for a 10.37 ERA in nine fitful games this month. It was hoped that a few days away from the grind could have a beneficial impact on the relievers that clearly needed a bullpen break.

Mission accomplished.

Francona called on both relievers after Penny had coughed up six runs through five innings, and placed Boston in a position where they couldn’t give up anything more. Any more damage done by Toronto would have risked the game spiraling completely out of reach, and both hurlers didn’t let that happen. Masterson and Ramirez combined for three scoreless innings with the sinkerballing Masterson setting down six straight right-handed hitters with steely efficiency in the sixth and seventh.

Scott Rolen battled Ramirez for a seven pitch walk to start the eighth inning, but he retired the next three Jays in order and fanned both Kevin Millar and Alex Rios to end his day’s work with a flourish. That bodes well for both key players in Boston’s second-half bullpen plans.