When the Cubs inked Jon Lester, it put a cap—at least until the team acquires another front-line starter—on a series of pitcher moves that will likely underwhelm the majority of Red Sox fans and fantasy players. Among Rick Porcello, Wade Miley, and Justin Masterson, Porcello is the closest to obvious fantasy relevance. Last season, he led the bunch with a 3.43 ERA and 1.8 walks per nine, but the three wins of real-world value are a more difficult fantasy sell for a pitcher who reached 200 innings pitched but failed to reach 130 strikeouts.
I’m more optimistic. The move from Detroit and Boston does not feature the obvious upgrade of an NL-to-AL trade, but a series of subtle situational improvements could together amount to a significant improvement in Porcello’s fantasy production. In particular, there are three ways I believe the Red Sox will improve Porcello’s numbers. They will:
1. Improve his defensive support
It is clear that the Red Sox value groundball pitchers. As Paul Swydan explained, all three of Porcello, Miley, and Masterson, as well as earlier-acquisition Joe Kelly, induce more groundballs than average. What is not clear is if the Red Sox have the defensive personnel in the infield to truly take advantage of a rotation with such an extreme tendency.
The right side of the infield should be up to the task. Dustin Pedroia has been an elite defender even in his more recent seasons that have featured declining offensive production. In fact, he has saved the Red Sox at least 10 runs at second base in four consecutive seasons per Defensive Runs Saved. In addition, Mike Napoli has been one of the best defensive first basemen in baseball (17 Runs Saved) since moving there for good at the start of the 2013 season.
The left side of the infield is more of a question mark. Newcomer Pablo Sandoval has alternated between some very positive and some very negative seasons at the hot corner. Xander Bogaerts, meanwhile, cost the team 17 runs split between shortstop and third base in his first full season in the majors in 2014. His youth and athleticism represents a promise of potential defensive improvement, but we do not have much to back that up statistically.
All told, the Red Sox could be an average defensive infield or they could be an exceptional one. And while that distinction could have a tangible impact on Porcello’s production, compared to his previous situation in Detroit, he almost definitely will be better off. The Tigers have been one of the worst defensive teams in baseball in each of the last three seasons, and while those deficiencies have not been limited to the infield, they have consistently been there.
|Rick Porcello’s Defense-Adjusted ERA, 2012-2014|
|Season||ERA||Tigers DRS||Infield DRS||Def. Adj. ERA|
I calculated a Defense-Adjusted ERA by apportioning the runs the Tigers cost all of their pitchers to Porcello based on his percentage of the total team innings. It is a back-of-the-envelope calculation—in truth, the team could have played better or worse defense behind Porcello than behind their other pitchers—but it should represent the approximate penalty Porcello suffered because of his team’s poor defensive play. Over the last three seasons, that penalty has been about a third of a run of ERA.
The defensive improvement Porcello should see in Boston is not limited to personnel. While defensive shifting has exploded in recent seasons across baseball, Detroit is one of the few teams—especially in the AL—that has lagged behind. In 2014, the Tigers shifted on just 205 balls in play according to Baseball Info Solutions. That is less than half the total of the AL team with the third-fewest shifts, the Mariners.
|Fewest Shifts, AL Teams, 2014|
Miley will benefit from an increase in defensive shifts but may not have a better defense behind him. Masterson should have a better defense behind him but will likely not see a dramatic increase in defensive shifts. Porcello is their one starter who can expect a dramatic improvement in both respects.
2. Earn him extra strike calls
The Red Sox’s new commitment to groundball pitchers may have less to do with the team’s relative defensive strengths and more to do with the overall MLB trend of an expanding strike zone. As Jon Roegele illustrated, the zone has particularly expanded below the knees, which one could hypothesize would increase the strikeout rates of groundball pitchers, in particular.
A key factor in those potentially elevated strikeout rates is quality pitch-framing, and the Red Sox may have recently promoted the best in the game. Jeff Sullivan dug into this in great detail and found Christian Vazquez was rated as the best pitch receiver on StatCorner and the second best on Baseball Prospectus in his limited major league time.
Looking at the full season, Jeff found that the Red Sox saw 96 extra strikes in 2014, a number one would expect to increase in 2015 with a full season of Vazquez as the starter. That may not represent a major improvement for Miley, whose former club, the Diamondbacks, saw 192 extra strike calls courtesy of Miguel Montero. However, Porcello should see a massive boost coming from the Tigers that had 114 fewer strikes called last season.
Jeff’s research suggests that each additional strike is worth approximately 0.14 runs. If you assume that about 20 extra strikes represent Porcello’s share of the framing improvement from the Tigers to the Red Sox, he would be expected to allow three fewer runs over the course of a full season. Subtract that annually from his three-year 3.74 Defense-Adjusted ERA and Porcello would have a 3.60 ERA.
3. Limit his home runs
Porcello has never had a major home run problem. For his career, he has allowed an 11.3 percent home run per flyball rate, which is only slightly above average. However, now that he will make his home starts in Fenway, he should start to see a few of those long balls stay in the park.
Fenway is famous for the Green Monster that turns some routine flyballs in the other 29 ballparks into cheap home runs, but it’s another story in right field. That split should be helpful for the right-handed Porcello since he has allowed 66 home runs to left-handed batters and 45 home runs to right-handed batters in his career. By rate, that is once every 38 plate appearances vs. left-handers and once every 45 plate appearances vs. right-handers. And in 2014, Fenway had the fourth-lowest home run index for left-handed hitters in baseball:
|Lowest HR Indices, LHB, 2014|
In contrast, Comerica Park in Detroit had a neutral 100 home run index for left-handed hitters in 2014.
Porcello has displayed all of the tools of a solid No. 4 fantasy starter in individual seasons. He had the 3.43 ERA and 1.23 WHIP in 2014. He had 142 strikeouts in 2013. He’s won at least 13 starts in four different seasons. With the advantages Boston should offer him, I think 2015 could be the season where Porcello realizes that potential in a single season. That coupled with his excellent track record of health—he has exceeded 175 innings pitched in four consecutive seasons—should make him a strong value if you can take him in the mid-50s or later among starting pitchers.
Scott Spratt is a fantasy sports writer for FanGraphs and Pro Football Focus. He is a Sloan Sports Conference Research Paper Competition and FSWA award winner. Feel free to ask him questions on Twitter – @Scott_Spratt