Should we be concerned about Jon Lester?

The Red Sox have been struggling lately, even with two impressive walk-off wins against the Rangers, much of which is due to the heroics of Darnell McDonald. The Sox haven't been very good at just about everything so far this year, for a nice example, the Red Sox have caught 3% of the runners attempting to steal on them. Three. A 97% success rate is absolutely unheard of for a single player, but V-Mart and Tek are turning every baserunner into a super Ricky Henderson. But their starting pitching, which was supposed to be their greatest strength, has been particularly disappointing. The Red Sox rank 13th in ERA in the AL, just beating out the lowly Royals.

Jon Lester was supposed to be the ace of the staff. Despite a slow start to 2009, he ended up with a 3.41 ERA, a 1.23 WHIP, and 225 strikeouts. To top it all off, his FIP (Fielding Independent Pitching, which is calculated based on strikeout, walk, and home run rates) indicated he was a bit unlucky, as his peripheral stats indicated he should have had an ERA of 3.15. After 3 rocky starts, Lester is sporting an 8.84 ERA and a 1.88 WHIP. Obviously he isn't that bad, but can he recover to ace status?

First, the good. Started off poorly last year, and may simply be a slow starter. Lester's ERA didn't get below 5.00 until June 12 of last year, and his monthly ERAs for April and May were 5.40 and 5.86 respectively. For the rest of the season Lester didn't post a monthly ERA above 3.07. But, when you take a closer look, things aren't quite so rosy. In 2009, Lester's strikeout and walk rates were excellent - over the course of April and May he struck out 74 batters in 65 1/3 innings (10.2 K/9 IP, which is actually higher than his strikeout rate for the entire season), while only walking 24. Because of the good strikeout and walk rates, we can probably chalk up Lester's poor start in 2009 to bad luck, and some bad defense. So far this season, Lester seems to be being bitten by bad luck too, giving up a .364 batting average on balls in play (.300 is average, and previous studies have shown that pitchers have very little control over their BABIP).

However, this season the strikeout and walk numbers have not been nearly as impressive as they were in 2009. A combination of fewer strikeouts (14 in 16 IP, which is still above average) and a much higher walk rate (9 in 14 IP, nearly twice the rate from last year) is a bit worrisome. , having already walked 9 batters, three in each of his starts. I'm not worried about Lester just yet, but control has been an issue for him in the past. The key here are the walks - he only had one three game stretch where he gave up 9 BB last year, but that was in 21 innings instead of 14. If he can't reign in the walk totals, he'll have to cede the title of "Red Sox ace" to Lackey or Beckett.