Red Sox haven't improved rotation enough

The Boston Red Sox were baseball's most disappointing team in 2012, with the Miami Marlins finishing a close second. After finishing at 90-72 in 2011, the Sox added Kelly Shoppach, Nick Punto, Mark Melancon, Andrew Bailey, Ryan Sweeney and Cody Ross before the season. They also added Marlon Byrd in April. However, with a 60-66 record on Aug. 25, they folded, sending Josh Beckett, Adrian Gonzalez, Carl Crawford and Punto to the Los Angeles Dodgers in the biggest salary dump baseball had ever seen -- a tacit admission that they had made some poor decisions.

This offseason has seen the Sox sign a few hitters: David Ross, Jonny Gomes and Shane Victorino (and, potentially still, Mike Napoli). Their only addition to 2012's third-worst starting rotation in the American League -- in terms of ERA -- was Ryan Dempster, while Koji Uehara and Joel Hanrahan were added to the bullpen.

The 2013 rotation will include Jon Lester (4.82 ERA in 2012), Dempster (3.38; 5.09 in the American League with the Rangers), Clay Buchholz (4.56), Felix Doubront (4.86), and John Lackey (injured). They need help, and they need it badly, whether it's from adding a new arm via free agency or trade (at this point in the offseason, not much is left out there), or from improvement from the other four over last season.

For Sox fans, there may be good news: Lester and Doubront are expected to enjoy 2013 a lot more according to ERA estimators. ERA estimators such as xFIP (expected fielding independent pitching) and SIERA (skill interactive earned run average) consider the factors a pitcher controls most -- strikeouts, walks and ground/fly balls -- to tell you what a pitcher's ERA should have been, which removes noise such as abnormal luck and extremely good or bad defense.

Lester's xFIP was 3.82 in 2012, exactly a full run lower than his ERA. I looked at pitchers who underperformed their xFIP by at least a full run going back to 2009. Twelve such pitchers were found; only three were worse the next year, while five improved by more than a full run. We would expect Lester to improve, but that doesn't mean there aren't concerns.

The lefty's strikeout rate has been in a three-year decline, from 27 percent in 2009 to 19 percent last year. More balls in play means more chances for hits and defensive miscues. To illustrate the difference, let's consider that last season, Lester faced 876 batters. The eight percent difference means 70 more balls put in play, and assuming his career average .301 BABIP, leads to 21 more hits. While ERA predictors take a pitcher's strikeout rate into account, Lester's decrease itself could signify a deeper issue.

As for Doubront, his first full season in 2012 featured some of the typical problems you'd expect of a player in his mid-20s in his inaugural run through the majors: too many walks and too many home runs. Among pitchers with at least 150 innings in 2012, Doubront's home run rate on a per-fly ball basis was the fifth-highest in baseball at nearly 16 percent (the league average is under 12 percent). His walk rate was the ninth-highest at 10 percent. Nevertheless, xFIP was more optimistic about his performance due to his prodigious ability to miss bats -- his 23 percent whiff rate ranked 21st out of 118 qualified starters.

While Lester and Doubront might regress towards their mean in a good way, and the addition of Dempster should help, the Sox shouldn't expect much from Buchholz and Lackey. Once viewed as a potential ace, Buchholz's profile leaves him as a bit of a Kyle Kendrick type: someone who is average in almost every possible way. And average isn't bad at the back of a rotation, but when you are praying for regression, you need more upside than one finds with Buchholz. Put another way, when you've just lost a big hand at poker and you're looking to win your money back, you're hoping for pocket kings, not pocket sixes.

As for Lackey, the veteran has had a tumultuous tenure with the Red Sox and will be entering 2013 recovering from Tommy John surgery. While there is a track record of pitchers having success after TJ surgery, there are no guarantees, particularly for a 34-year-old such as Lackey. In 2011, his last full season, he posted a career-low strikeout rate (14.5 percent) and finished with a strikeout-to-walk ratio under two for the first time in his 10-year career. To expect anything better than replacement-level pitching from Lackey would be a fool's errand.

When you look at the Red Sox rotation in its entirety, you have two pitchers who you're hoping were only bitten by bad luck in 2012, a free agent who has only been slightly above-average in recent years, a youngster who may have already hit his ceiling, and a veteran surrounded by a thousand question marks. The Red Sox, who last year won fewer than 70 games for the first time since 1965 (excluding strike-shortened seasons), don't appear to have done enough to upgrade what was one of the worst starting rotations in the league.

Few choices remain in free agency, with most best categorized as veteran retreads, but there are a few that should catch Ben Cherington's eye: Shaun Marcum, Kyle Lohse and Jeff Karstens. Marcum is a bit of an injury risk as he suffered from elbow problems last year with the Milwaukee Brewers, but the upside is that he would fit in well around Lester at the top of the rotation. Lohse is a proven veteran who appears to have taken big strides in his last two seasons with the St. Louis Cardinals, becoming incredibly stingy allowing walks. Karstens is an underrated right-hander, similar in many ways to Lohse, but would come at a much cheaper price.

If the Red Sox are done adding to their rotation between now and the start of the regular season, it doesn't appear like they will have nearly enough to compete with the restocked Toronto Blue Jays and the rest of the hyper-competitive AL East.