BALTIMORE -- And now, a brief respite from the unrelenting negativity of the Red Sox' season to note a (gasp) considerably promising development in the team's season.

The Red Sox have been terrible this year. The rotation has performed horrendously. Still, the team now appears to have a considerable building block going forward in left-hander Felix Doubront.

Doubront delivered a strong punctuation mark to what proved a tremendous performance in his last two-plus weeks of the season. Though he suffered the loss in Boston's 4-3 defeat against the Orioles, the left-hander logged seven innings in which he allowed four runs (three earned) while punching out 10 and walking one.

That marked the fourth straight start in which Doubront had turned in a quality start (6+ innings, 3 or fewer earned runs), the longest such streak of the 24-year-old's young career. Moreover, he logged seven innings in his final two starts of the year (two of his three seven-inning outings this year), and he finished the season with the first two double-digit strikeout games of his career.

The stuff? On Saturday, electric. Doubront elicited 14 swings and misses in his 107 pitches -- eight on his fastball (which registered as high as 95 mph), one on his changeup, five on his curve. Perhaps more significantly, in his final two starts of the year -- at a time when he'd obliterated his previous single-season career-high in innings -- he showed the ability to work deep into the game while maintaining his stuff. That's an important development, since the left-hander's arsenal is unquestioned.

"Doubront's probably got the best stuff in the league, as far as I'm concerned, with his velocity, with the way the ball moves," said catcher Jarrod Saltalamacchia, without any apparent intent of hyperbole. "He's got four pitches he can throw for a strike at any time, and most of the time he only uses three of them. He's got really good makeup, and I think this first year under his belt is going to be really big for him."

Doubront has the ability to get swings and misses with a four-pitch mix, something that is both one of his foremost attributes but that also represents something of a challenge, since his high swing-and-miss rate tends to make pitch efficiency an issue. He struggled with that double-edged sword while with Double-A Portland in 2009. In 26 starts, he had a 3.35 ERA and 7.5 strikeouts per nine innings, but he averaged 4 2/3 innings per start, and pitched more than five innings in just four of his outings. The next year, however, he became more effective and more efficient, with a 2.81 ERA and 8.1 strikeouts per nine innings in 17 minor league outings in Double-A and Triple-A, resulting in his first taste of the big leagues.

So, he's shown the ability to make strides to address shortcomings before. This year, he showed that ability within the course of the season. In his final two starts -- both against the Orioles -- he showed improved tempo and pace, with excellent execution. He walks away from the 2012 season having reached a career-high in innings (161) and starts (29), and despite the length of the season, he was pitching arguably his best baseball of the year at the season's end.

"He's worked quicker, looks much better, so I think when a young guy improves right up until the last game of the season, I think that's a good thing," said manager Bobby Valentine. "I think it's a great season to build on."

"That was the best, my last four games," said Doubront, who finished the season with an 11-10 record and 4.86 ERA. "That was one of my goals, to finish strong. I learned a lot of things about the game, about pitching, that’s what I’m proud of most."

Doubront went through a full season (save for a brief DL stint in August) and lived to talk about it. But in stepping back and looking at his year more broadly, he did far more than merely survive.

A few notes worth considering on Doubront's year:

• He finished the season with 167 strikeouts, most by a Red Sox left-hander age 24 or younger since Babe Ruth (!) had 170 punchouts in 1916.
• However, Ruth, then 21, needed more than 300 innings to pull the trick. His strikeouts per nine rate in 1916: 4.7. Doubront this year: 9.3 strikeouts per nine innings, roughly double Ruth's rate of punchouts. Number of Red Sox left-handers age 24 or younger with such a punchout rate in at least 150 innings pitched: 1 (Doubront).
• Number of left-handers in major league history with a season of at least 9.0 strikeouts per nine innings and 150+ innings pitched at age 24 or younger: 12. The list:
  
  Clayton Kershaw (4 seasons through age 24, including a Cy Young award at age 23)
  Sam McDowell (3, en route to 6 All-Star appearances)
  Scott Kazmir (2, en route to an eventual two All-Star appearances)
  Sandy Koufax (2, en route to a Hall of Fame career that included 3 Cy Young awards and an MVP trophy)
  Herb Score (2, both All-Star seasons)
  Oliver Perez
  Johan Santana (two-time Cy guy)
  Rick Ankiel
  Sid Fernandez (two-time All-Star)
  Frank Tanana (four-time All-Star)
  Tom Hall
  Doubront
  
  Obviously, pitchers like Perez and Ankiel serve as cautionary tales for this select group, but most of the players who produced the kind of strikeout rate that Doubront delivered this year achieved elite status.
• Number of Red Sox of any handedness to average at least a strikeout an inning with a minimum of 150 innings pitched at age 24 or younger: 1 (Doubront). Jon Lester never did it. Roger Clemens never did it. Clay Buchholz didn't do it.
• In 10 starts against the top three teams in the American League East (the Orioles, Yankees and Rays) this year, Doubront had a combined 3-3 record and 3.06 ERA with 29 walks (4.2 per nine innings) and a whopping 75 strikeouts (10.9 per nine).

So what is he?

The Sox had long felt that the left-hander's performance throughout the minors had flown below the radar. They saw a big, sturdy pitcher with a great frame to assume a considerable workload and the ability to throw three or four pitches for strikes.

Baseball America never ranked him among a league's top 10 prospects at any level. Within the Sox system, he ranked as the 18th best prospect after the 2006 season, went unranked after a dreadful 2007 campaign, returned to the radar at No. 27 after 2008 and No. 18 after 2009, jumped up for one brief moment to the No. 5 prospect in the system after the 2010 season and then slid back to the No. 17 Red Sox prospect after an injury-riddled 2011 campaign.

The Sox, however, felt internally that he had the floor of a back-of-the-rotation (No. 4 or 5) starter with the ceiling of a No. 3-4 starter. In his first taste of a full season in the big league rotation, he did nothing to discourage such an outlook.

Indeed, if anything, given the unusually high strikeout rates he produced, there are some who insist that the suggestion of a mid-rotation ceiling might be a bit too conservative.

Daniel Bard has seen Doubront over much of his career. The two pitched together in 2007 and 2008 in Single-A Greenville, and so Bard can appreciate the progress that the left-hander has made.

"Even though he's a lot younger than me, he still moved up really quick. I think we saw flashes the last couple years out of the bullpen of how good his stuff is. He maybe wasn't able to piece it together as a starter," said Bard. "His stuff's gotten better. He didn't throw this hard when he was younger. He's one of the few guys you see whose velocity keeps climbing. I caught the end of his warmup [on Saturday], right when we were walking out there, probably the last 10 pitches, he was locating on the knees, both sides of the plate, with all the pitches I saw. It was pretty impressive. He's pretty close I think to being I think elite in this league."

Elite? As in top of the rotation?

"I would say so, yeah. For sure. What's missing?" mused Bard. "When he gets cruising, he's as good as anybody. He's impossible to hit. He [gets strikeouts] with his fastball. It's not with a great curveball or something. If you can win with your fastball in this league, you're going to win a lot, because you can always go to that secondary stuff. If you force them to sit on the fastball, you're going to have a lot of success."

As the Sox try to position themselves for contention, Doubront gives them a legitimate arm for the rotation going forward. Given his relative youth, the fact that he'll finish the year with an ERA that is slightly worse than league average requires some context. He demonstrated the raw materials to be an above-average big league starter, he boosted his innings to the point where he won't face any predetermined restrictions in 2013 and he showed the aptitude to get better as he nudges closer to his prime.

In Jon Lester, Clay Buchholz and Doubront, the Sox now have three homegrown starters with a demonstrated ability to compete in the American League East. While Doubront delivered mixed results in 2012, the left-hander's progress throughout his professional career suggests a pitcher capable of playing a very important role going forward.

"I was with him when we won the [Rookie Level] GCL championship in '06. I think his stuff has always been there. It's just been maturing, growing up and learning how to use it that's gotten him to this point," said outfielder Ryan Kalish. "It's just about him growing up as a person and as a player, learning what his strengths are. I see what he's doing as a formula for success for a really long time."