When his team needed him the most, he struggled. Behind clubhouse doors, he was more of a follower than a leader. The left-hander plans on changing all that in 2012.
Lester, 28, met with the media at the player development complex on Sunday and spoke at length about his disappointing 2011 season and took responsibility for his actions both on and off the field.
He promises to be a better teammate moving forward and would like to take on more of a leadership role now that he considers himself a veteran. Lester said all the right things, but the true test will be whether he acts like a true leader on and off the field.
"I want to try to," Lester said. "It's something that, kind of the guys in my age group never had to do because we've been around guys like [Tim Wakefield] and [Jason Varitek] and had veteran guys who had been around for a long time. We've kind of sat back and let them do their thing and followed them, so I think it's time for us, and me, to step up and try to feel comfortable in that situation and try to do the best I can in it."
When Lester was working his way through the organization's development system, he would watch and absorb as much as he could from veteran pitchers, including Curt Schilling, Wakefield, Mike Timlin and Josh Beckett.
Lester sat next to Wakefield in the Red Sox clubhouse at Fenway Park. Lester has become extremely close with Beckett. Lester says he now wants to be a role model for the younger pitchers in camp.
"Hopefully by me going out and pitching and doing the stuff in the weight room in between starts, young kids can see that and say, 'All right, this is what I need to do,'" Lester said.
When asked how he planned on "stepping up" his leadership qualities, Lester said he would lead by example.
"Being a better teammate and having a better presence," he said. "A guy like Tek, if you watch Tek, he never really says much, but his presence is just enough. I think going out here, we've got a lot of young kids in camp and it's showing them that the first bullpen means something. The first sprints mean something. The first ground ball, PFPs [pitchers' fielding practice] are important and it sets the tone for the season."
New Red Sox manager Bobby Valentine has been impressed with both Lester and Beckett so far in camp.
"When you see Josh Beckett and Jon Lester here, they are atop the pyramid as far as the pitchers are concerned, and they came early and they've been showing fantastic attitude," Valentine said. "So far that attitude with the pitching staff seems to be filtering down."
On the mound in 2011, Lester did not reach the 200-inning plateau, which is something he strives for every season. In fact, it was the first time as a full-time starter in the big leagues that he failed to reach that mark. Since the 2008 season, Lester pitched 210, 203 and 208 innings respectively until he fell short with 191 2/3 innings in 31 starts in 2011.
"That's my goal every year," Lester said. "Regardless of what the staff looks like, I want to make 30 starts and hopefully with those 30 starts, you get to 200 innings. Last year I was eight short and I felt like a failure. I don't feel like I got to where I needed to be. If I'm able to pitch 200 innings, everything else will take care of itself. That's a big number for me and that's something I strive to get to every year."
Off the field in 2011, there were incidents that occurred in the clubhouse with some of the starting pitchers during games that Lester said he's not proud of, and he says he has learned from his mistakes.
When the season ended, reports leaked from the clubhouse that some pitchers ate fried chicken and drank beer occasionally during games when they were not pitching. Those stories, and the fact that the rotation struggled during the historic September collapse, gave the team -- and the starting pitchers in particular -- a massive black eye.
"I hope [fans] don't have a different perception of me," Lester said. "I'm still the same guy. I'm still the same person I was five years ago. I care a lot about this team. I care a lot about my job. I hope the fans realize that stuff had nothing to do with what happened on the field. I stunk. We stunk and we're looking forward to proving people wrong.
"Last year, everyone wanted to give us the World Series title the first day, and this year I think we're coming in as underdogs and that's going to be fun. It's going to be fun to see how guys react and how we go about our business."
Lester has been known to start slow and finish strong, but Boston's ace went 1-3 in six starts during September.
"It's disappointing. It's a crucial time of the year and I'm supposed to pitch good and I didn't," he said. "I don't know why. Physically, it was September and I felt fine. I tried to grind through it but it was one of those things."
He claims that failure weighed on his mind during the offseason and he hopes to build off of that for this year.
"Usually, as soon as the season ends I go home and don't think about baseball. I'm done and I move on," Lester said. "This year it lingered in my head, and I think that helped motivate me to get into the gym more and start moving back to baseball. I have more desire this year."
Joe McDonald covers the Red Sox for ESPNBoston.com.