Almost everything about Jon Lester's track record is viewed through a surprisingly critical lens. The left-hander's excellence from 2008-11 was historically good yet arguably underappreciated. His struggles in 2012 were real yet perhaps treated as more dramatic than they actually were.

Of course, when it came to last season, the fact that Lester's worst big league season looked so glaring was precisely because he'd been so good and so consistent in the previous four years.

Between the ages of 24 and 27, he turned in four consecutive years of at least 190 innings, 15 wins and an ERA of below 3.50, making a pair of All-Star teams in the process. In each of those years, his ERA+ (ERA compared to the league average, adjusted for the ballpark in which he was pitching, with 100 representing league average) ranged between 144 and 124, meaning a pitcher who was at least 20 percent better than league average in each of those four seasons.

To put that in some context: Lester became the 16th pitcher since 1901 to post four straight seasons between the ages of 24-27 in which he a) pitched enough innings to qualify for the ERA title and b) had an ERA+ of 120 or better in each of those years. (Matt Cain became the 17th member of the group last year.) Of the previous 15, nine are now Hall of Famers.

Obviously, that's select company. At the same time, Lester came off the rails in 2012 in a fashion that few of his predecessors had.

Last season was, of course, a brutal one for the left-hander. Though he made all 33 starts and logged 205 1/3 innings, he went 9-14 with a career-worst 4.82 ERA and an ERA+ of 90, suggesting a pitcher who performed to a standard that was 10 percent worse than league average. An ERA+ of 90 -- slightly but not horribly below average -- is a bad but not horrifying outcome, though in light of the consistency he'd demonstrated in the prior four campaigns, perhaps it is unsurprising that his year was treated as catastrophic, particularly in light of the fact that it contributed to a void at the top of the Sox rotation.

Of course, at this juncture, what happened to Lester in 2012 is far less important than what might be expected from him in 2013. What does history suggest about his ability to bounce back?

Of the first 15 members of the group of pitchers that demonstrated the kind of year-after-year excellence of Lester between ages 24-27, almost none endured an age 28 season like Lester's. Almost.

But one of the pitchers in the group performed to a below-average level in his age 28 season. That was former Blue Jays ace Dave Stieb, a hurler who was arguably as dominant as any in the American League in the '80s.

But in 1986, coming off a season in which he led the AL in ERA with a 2.48 mark, Stieb endured a hiccup, going 7-12 with a 4.74 ERA and an ERA+ of 89. That season tracked closely with the one that Lester just endured.

"What happens with those guys who are so dominant is that when they're off by that much, every hitter in the world wants to get a measure of payback," said Blue Jays analyst Buck Martinez, who caught Stieb that season. "Stieb was so dominant, just like Jon. He was a Cy Young candidate. Had he been on good teams, he would have won 25 games. But I think it was just a matter of, his slider wasn't quite as sharp and that was his bread and butter. It caught up with him that one year but he bounced back and became a better pitcher."

Indeed, Stieb recovered to emerge as better than league average in 1988 (111 ERA+), and indeed, over the next four years, he was good for 30-plus starts a year, a 3.33 ERA and an ERA+ of 121.

Jim Palmer likewise saw his ERA+ decline from 140 between his age 24-27 seasons to 105 at age 28; at age 29, he returned to complete dominance, going 23-11 with a 2.09 ERA and a 169 ERA+. He was an elite starter in perennial Cy Young contention for four additional years.

So Lester can derive hope from the select group with whom he kept company between ages 24-27. That said, it's not all good news.

Of the 15 players prior to Lester (and Cain) to have an ERA+ of 120 or better between ages 24-27, six suffered declines relative to the league average in both their age 28 and age 29 seasons. Of course, four of those pitchers were still good enough to reach the Hall of Fame (Walter Johnson, Robin Roberts, Bert Blyleven, Hal Newhouser).

What does that suggest? Broadly, that pitchers whose careers are characterized by consistent dominance nonetheless experience ups and downs in various seasons that are typical of more mortal pitchers. Even in a dominant pitcher's peak seasons, a year that is a struggle isn't an unprecedented or even shocking development. However, great pitchers manage to isolate their struggles and recover from them. The question then becomes: Can Lester do just that?

Certainly, the left-hander and his team believe that he is capable of doing so, suggesting that 2012 represented a product of clear mechanical struggles rather than a signal that he no longer had top-of-the-rotation stuff.

In many respects, Lester's season came unglued in the course of a three-start stretch around the All-Star break. In losses to the Yankees, White Sox and Blue Jays, he yielded 22 runs (21 earned) in 12 1/3 innings, lasting no more than 4 1/3 innings in any of the outings.

At that point, the problems were glaringly mechanical. He'd lost his direction to the plate, with ugly results that culminated in the 11-run, four-inning yield against the Blue Jays.

"Those starts after the All-Star break, where I think I was figuring things out and 4 1/3 was, I think, the most I went, I wish I could take those away," Lester said at the end of the year. "I think this year would be not necessarily good by any means, but salvageable."

From that point forward, he made a number of adjustments that permitted progress. In his final 13 starts of 2012, Lester had a 3.92 ERA. Absent those three outings, he would have finished the year with a 4.15 ERA rather than the jarring 4.82 mark that was more than a run worse than his career norm.

The fact that he was able to make a number of adjustments on the mound to more closely approximate his career standards left the left-hander with some optimism heading into the offseason.

"I fell into some bad habits. I finally figured out what those bad habits are, or were, and corrected them," he said at the end of the year. "Now, I feel like myself. I don't feel like I'm getting the results I want, but I feel like I'm pitching better. The stuff is there. My cutter's got a better shape. My curveball's got better finish. My fastball's got life back in it. I'm missing to the side of the plate I want. I'm down in the zone. So, with that being said, now it's all about results. If I stick to those things, fingers crossed, stick to the process and the results will be there.

"I'm not going to change anything this offseason. I'm going to do the exact same thing I've done: Work my ass off, come to spring training and get back to the biggest thing, which for me is feeling like me on the mound," he added. "If I can carry that over to the offseason, build on that, get the repetitions, I should be back to where I was."

Lester is now in Fort Myers, at the start of a season that may prove pivotal both for him personally and for his team. Will 2012 prove an exception or a trend? The answers might soon start to become apparent.