As we begin to creep up on the halfway point of the season, it’s worth taking a look at the Red Sox starting rotation to see how things have gone, how they’re going and where they might be headed. While the pitching has certainly cooled off lately with nearly everyone in the rotation experiencing some kind of mini-slump since mid-May, Red Sox starters have combined for the ninth best ERA in baseball and the seventh best xFIP, suggesting that while there might be some room for improvement, this is a mostly solid group. Let’s jump right in and take a look…

Clay Buchholz (1.71 ERA, 2.49 FIP, 3.24 xFIP, 3.47 SIERA)

As far as the results are concerned, Buchholz has been one of the best hurlers in the Majors and the clear-cut best pitcher in the Red Sox starting rotation. While the results so far have been mainly positive, there’s a very big reason to take pause.

Luck.

Not only is Clay sitting on a very friendly .258 BABIP, but also his LOB% and HR/FB% are both within the top five among Major League starting pitchers. Long story, short – it’s not so much a question as to whether he’ll regress, but more of a question of how deep that regression will be.

The good news is that his 3.51 xFIP lines up well with his 3.47 SIERA which would suggest that even if the regression is hard, he should still be among the best starters in the division heading forward. Barring any major health concerns, people should expect him to continue his excellent year.

Jon Lester (4.12 ERA, 4.18 FIP, 4.02 xFIP, 3.82 SIERA)

If there’s one thing I hate about baseball folks, it’s their tendency to judge players on the basis of what they wished they were as opposed to what they actually are. Such is the case with Jon Lester.

After three years of mostly similar performance, I think it’s fair to say that he’s probably never going to return to his 2009-2010 form. He’s not an ‘ace’ and no, he won’t become one with the help of another coach or anything like that. And you know what? That’s OK!

Lester’s still a really good pitcher. He strikes guys out, has good control and chews innings. He’s not an elite pitcher, largely because unlike the Justin Verlander’s and Felix Hernandez’s of the world, Lester can’t control his mechanics as consistently as they can and as such – is prone to extended periods of wildness that inflate his numbers.

Basically – he’s what most #2/#3 starters are. Lester’s not having a bad year at all. He’s just not having as good a year as a lot of people think he SHOULD be having based on skills he hasn’t had in three seasons.

Felix Doubront

Red Sox pitchers mingle. (CREDIT: FLICKR)

Yes, he’s in the midst of another slump, and yes he grumbles and double yes – it can all get grating at times. But this is what he’s always done and the 2-3 poor starts every 2-3 months are dwarfed by his 10 -15 solid to excellent starts. His walk rate has been inflated by three awful outings. So has his ERA and so has his FIP. Yes, he was that bad in those starts. But he’s also been that good in others.

Long story, short – It’s a slump. He’ll be fine. He’s also not a #1, and that’s also fine. Expect more of the same.

Felix Doubront (4.84 ERA, 3.64 FIP, 3.64 xFIP, 3.89 SIERA)

While it’s clear that Doubront still needs to become more efficient with his pitches and walk fewer batters, there’s still a lot to be said for his performance once you strip away all the bad luck he’s had this year. In fact, Doubront has been bitten harder by the luck dragon than any other pitcher on the Red Sox staff; posting an identical FIP and xFIP (3.64) that’s a full run better than his ERA (4.84).

What’s responsible for the disparity between his performance and the results? It appears that the primary culprits are a low strand rate (69.9%) and a sky-high BABIP of .356.

Basically, he’s walking too many batters, hits are falling in that normally wouldn’t and many of those runners are scoring. Still –even with his efficiency issues and high walk rate, he should be getting far better results than he has. Take away the bad luck, and Doubront’s been well above average. Simply put, the skill has been there. The results have not.

The lingering question I have about Doubront is his physical ability to pitch past his career IP mark. Last year, he camped on a perfectly fine 3.72 FIP up until he hit around 125-130IP. After that, he ran out of gas and his numbers inflated. If that threshold does exist this year, it’ll be interesting to see what it might be. Given his poor performance post-cap last year, it’s something the Red Sox will surely be keeping a watchful eye on.

John Lackey (3.14 ERA, 4.24 FIP, 3.51 xFIP, 3.45 SIERA)

John Lackey’s resurgence has easily been one of the best things to happen to the Red Sox so far this season. Sure, he’s been very HR prone, but outside of that, everything not only seems to be working, but it seems to be for real. The only two things to keep an eye on will be his inflated K/9 and his arm strength as the season progresses. One might cause a bit of regression while the other is just common-sense due diligence for a guy coming off Tommy John. They’ll also need him to work deeper into games but again – that’s really more of an arm strength thing more than anything else. As the season plods along, expect Lackey to start chewing some more innings again. All things considered though, you have to feel good about what he’s done so far and even better – there’s little reason to think he can’t keep it up and dare I say – improve.

Ryan Dempster (4.40 ERA, 4.75 FIP, 3.84 xFIP, 3.76 SIERA)

The thing about Ryan Dempster is that he’s been so consistent through the years, that base lining his performance is really easy compared to a lot of other guys. This year, his performance has been a bit more slapstick – but not to a point where people should be getting worried.

The good news in all of this is that Dempster’s xFIP is a full run higher than his actual FIP. While it’s true that HR’s have always pestered Dempster throughout his career, I wouldn’t worry too much here as his 17.5 HR/FB% is well above his career average. Unless there are health issues or he’s suddenly forgotten how to pitch, I’d expect that he’ll snap out of this slump he’s in fairly quickly.

Throughout his career, he’s maintained a relentlessly pedestrian 3.70-ish SIERA. Of course this year, he’s doing the same thing. Like Doubront, he’s a pitcher who’s showing the skill and not getting the results.