The pressure is on Jon Lester.
That has nothing to do with his first career Opening Day start Friday. For someone who has tossed a no-hitter and won the deciding game of a World Series, starting the opener is more of an honor than a test.
But after he's struggled out of the gate for three straight seasons, the pressure is on Lester to overcome his history of slow starts.
In his career, Lester is just 3-6 with a 4.76 ERA before May 1. After April, he's a different pitcher, nearly unbeatable at 58-19.
Lester's .709 career winning percentage is the third highest in MLB history (minimum 60 decisions). But if you look only at results after April, he's the best ever. At .753, Lester tops the rather obscure 1920s pitcher Emil Yde, who went 1-6 in his career in April but 48-19 afterward.
Lester's historic performance has set a nearly impossible precedent. But the question remains: Can Lester's excellence translate to April?
In his three full seasons in the majors, the trend is unmistakable. Lester endures an early stretch in which he struggles with rhythm and command. Once he settles in, there's almost no one better.
Last season, Lester was 0-2 with an 8.44 ERA after three starts. Opponents were batting .313, and he'd issued nine walks and hit two batters in 16 innings. As amazing as it sounds, Lester was the weak link in a Boston Red Sox starting rotation that otherwise boasted a 3.19 ERA at the time.
Yet, after that, you'd be hard-pressed to find a better starter in the American League. Lester went 19-7 with a 2.81 ERA to finish the season. That matched CC Sabathia for the most wins in the AL from April 19 on.
It's not an exaggeration to say that Lester's first three starts might have cost him a shot at the Cy Young Award. Would 20 wins and a sub-3.00 ERA have been enough to overtake Felix Hernandez?
Prior to his final appearance (4 IP, 8 ER with the Red Sox out of playoff contention), Lester had a 2.49 ERA after the poor April stretch.
These slow starts have been evident from the outset of his career. He's allowed 13 earned runs in 14 innings (8.35 ERA) in his past three season openers.
In each case, Lester's Grapefruit League numbers haven't foretold his struggles. From 2008 to 2010, he was 5-2 with a 3.28 ERA in spring training.
Before April 15, Lester is 1-5 with a 6.75 ERA in his career. But when he has turned it around has varied from year to year. In 2010, he finished April with 13 1/3 consecutive scoreless innings.
In 2009, Lester was 1-2 with a 5.40 ERA to end April, as his slump lasted three starts into May. The year before that, he managed to turn things around in his final start of April, tossing eight shutout innings.
The frustration of this recurring problem was evident last April. "Every year I tell myself it's not going to happen, and it still does," he told the Boston Globe prior to allowing seven runs to the Rays. "If I had an answer, I would try and fix it."
There's no simple statistical explanation for Lester's struggles. After he got in a groove last season, former pitching coach John Farrell told the Boston Herald that Lester's "focus and effort level have been more consistent from pitch to pitch."
For his part, Lester has cited a need for repetition and getting into a rhythm.
"Once you're able to repeat everything and get a base for it, that's when you get on that roll in the middle of the season," he told the Providence Journal in February. "People always wonder why pitchers don't do well at the beginning of the season. Well, you're still building. You can only do so much with what your body allows you to do. You're playing games that mean something for the first time. You've got to continue to build. It takes CC until June, and he's unbeatable from then on. Everybody is different. Everybody has different bodies and they work differently. You just have to do what the game gives you."
Although concepts like focus, effort and repetition are rather intangible, some statistical trends have emerged from Lester's slow starts. Among them are a lower ground ball rate and more walks.
Looking at Lester's three slow starts combined, a major factor appears to be a lack of command of his offspeed pitches. In his early struggles, Lester has thrown his curveball for a strike just 51.6 percent of the time, according to Inside Edge. Otherwise, his curve has a 58.2 strike percentage.
Opponents chased just 21.5 percent of the curves thrown out of the zone during the slow starts. That has jumped to 32.3 percent once he's gotten rolling.
Other traits of Lester's struggles seem to vary from year to year. Case in point, his performance against lefties.
In 2008, lefties hit .333 in his first four appearances but just .198 after that. But in 2009, he succeeded against lefties despite other struggles. Last year, it took another interesting turn.
In 2010, lefties hit .350 off Lester in his first three starts and just .211 for the rest of season. Of all things, it was his fastball that was the culprit. Lefties hit .438 on at-bats ending in his fastball for the first three starts. Over the rest of the season, they hit just .227 on such at-bats.
Only seven left-handed batters pulled a Lester fastball for a hit last season. Three of those came in his first three starts. Lester gave up three hits to lefties on inside fastballs in those first three starts. Over the rest of the season, he allowed just one.
Until he starts strong, Lester's numbers will continue to be picked apart in search of some answer. But perhaps there's no single diagnosis to be made. Lester simply requires time to find his comfort level.
For a pitcher who has achieved so much, Lester's April struggles are a reminder that he can still improve. That progress can begin Friday, when he has another chance to start out as the pitcher he always becomes.
Jeremy Lundblad is a senior researcher with ESPN Stats & Information. He provides statistical analysis for ESPNBoston.com.