Positional series: Rotation looks solid

This is the fourth in a weekly series evaluating the Red Sox roster by category: infield, outfield, catching, starting pitching, bullpen and DH.

Talk about a conversation-changer. Entering spring training last year, pitcher Jon Lester was expressing uncertainty over whether the Red Sox intended to exercise the contract option they held on him for 2014.

Now, with the option picked up and after a postseason performance that rivaled the best of Josh Beckett, Curt Schilling or Pedro Martinez, Lester is assuring Sox fans that he’d rather not walk away just to cash in as a free agent but hopes to end his career in a Red Sox uniform. And that scenario also is appealing to the Red Sox.

Reunited with former pitching coach John Farrell as his manager and a driven Juan Nieves as pitching coach, Lester regained the form that had made him one of the American League’s most successful left-handers, halting a declining strikeout rate (it ticked upward to 7.5 K’s per 9 IP from 7.3), keeping the ball in the ballpark (19 home runs allowed to 25), regaining command of his four-seam fastball in the strike zone and getting back the chase-and-miss effectiveness of his cutter.

Lester temporarily veered off course in June (7.62 ERA in five starts), but posted a 2.89 ERA in 16 starts the rest of the way, leading into a virtuoso October in which he held the opposition to six earned runs in 34 innings, a 1.59 ERA.

Lester himself admits he’s no Clayton Kershaw, but he has won 15 or more games in five of his six full seasons competing in the tough AL East, last season pitched a career-high 213 1/3 innings -- the fifth time he has pitched 200 or more innings -- and by his own admission became a better teammate in 2013. It was startling to hear him say at the Boston Baseball Writers dinner that until 2013, he only cared about what he had to do once every five days. Not coincidentally, he also said he never knew until last season that you could actually have fun playing baseball in Boston.

Lester thus enters this season as the unquestioned leader of a Red Sox rotation that made a huge improvement from 2012, when it finished the season with a 5.19 ERA that was third worst in the American League. Last season, the Sox ranked fourth in ERA (3.84), opponents’ OPS (.709) and strikeouts per nine innings (7.59), even though it walked the second-most hitters in the league (351).

Besides Lester’s bounce-back year, John Lackey shed his previous Boston incarnation, replacing it with a dramatically streamlined, healthier version reminiscent of his best days with the Angels, when he served as staff stopper. The velocity returned, and the strike-throwing was remarkable (1.9 walks per 9 IP).

Clay Buchholz was baseball’s most dominant pitcher for the season’s first two months, left-hander Felix Doubront made significant strides in his second full season as a starter, and veterans Ryan Dempster and Jake Peavy filled out the back end of the rotation, Peavy giving the Sox 10 competitive starts after coming in a trade-deadline deal with the White Sox and Tigers.

And everyone is back, including Peavy for a full season, while the number of young pitchers clamoring for a look is growing larger, led by Brandon Workman, who did well in his first big-league exposure last season. Allen Webster, Rubby de la Rosa, knuckleballer Steven Wright, and Portland graduates Matt Barnes and Anthony Ranaudo give the Sox their best group of young arms in some time, with exciting left-hander Henry Owens, who should begin the year in Portland, rapidly catching up. Some of them will wash out along the way, but the Sox are sufficiently confident with what’s in the pipeline that they stayed out of the Masahiro Tanaka bidding.

Still, there are issues. Buchholz was sidelined three months last season with shoulder bursitis and pitched on fumes in October. He avoided surgery this winter, but his durability remains a question. Dempster turns 37 and Peavy 33 in May; Lackey is 35. Dempster would seem to be the most likely candidate to be odd man out of the rotation, but the Sox figure to need anywhere from eight to a dozen or more starters before October, so he’s not a bad guy to have in reserve.

Lester would like a contract extension before Opening Day, but even if he doesn’t get one, he’s already shown an ability to thrive in a contract year. Buchholz has replaced Lackey as the biggest question mark coming into camp, but if he’s as healthy as the Sox insist he is, this is a rotation built to succeed.

Click here for the rest of the positional series.