The rise and (mostly) fall of the 2015 Red Sox rotation

The Red Sox rotation has been a bit of a roller coaster so far this season. Many were skeptical entering the season, and feared it wasn't good enough to win a World Series. The Red Sox didn't make a deal for Cole Hamels like many expected, but rather opted to give their high upside rotation the opportunity to show what they could do. Well, what we've seen has been a rotation that can implode at the blink of an eye. This rotation has had several games where their starter is an out, or double play away from getting out of an inning, but somehow manage to allow their opposition to put up a five spot in the inning.

This implosion resulted in a team that gave up ten or more runs in four games through the first month of the season. Their starters failed to get through the fifth inning eight times, and also gave up five or more runs eight times as well, which ranks as one of the worst in baseball in each of these categories. The fact that their starters imploded so frequently is even more detrimental when you look at the struggles of their bullpen. The advanced statistics show that their bullpen was one of the worst in baseball, and had the third worst fWAR of -0.2.

Through the first month of the season, their rotation had the worst ERA in all of baseball. But, as we all know, ERA is not a fair statistic to measure a pitcher's overall performance. In fact, when we take a look at the advanced metrics of FIP, xFIP, and SIERA, we see a rotation that's just slightly below the middle of the pack. And while that isn't great, it shows us that they haven't been as bad as their ERA says. It doesn't help that their defense has been one of the worst, and ranked in the bottom five in defensive runs saved in April with -16.

After examining their PITCHf/x data, one thing that stood out is how their rotation is approaching hitters. These starters are almost exclusively living on the outside corner. One of the oldest cardinal rules in baseball for pitchers, is that in order to be a successful pitcher, you must be able to pitch inside. Dominating the inside of the plate, especially with the fastball, allows pitchers to more effectively use the outer half of the plate- which can lead to batters chasing breaking and off speed pitches out of the zone. Here's the zone profiles of the rotation against right handed hitters. The profile against lefties is generally the same, of pitching them away, but I didn't want to overload this article with images.

As we can see, these guys are mostly utilizing the outer portion of the plate, but not really attacking the inner half of the plate- with the exception of Porcello who is using both sides of the plate. Pitchers like to pitch away because most batters do not have great opposite field power, and many tend to roll over on pitches away that result in weak grounders. However, if pitchers are primarily living on the outer half of the plate, hitters start to stride towards the outer half and dive into balls which makes hitting the outside pitch a much easier thing to do. Another cause for concern is the fact that their rotation is failing to get strike one. Their first pitch strike percentage as a rotation currently ranks 28th in baseball at 57.4 percent which is obviously not what you want.

This rotation is essentially not doing two of the more important things that pitchers need to do- get the first pitch strike, and utilize the inner half of the plate to set up breaking and off speed pitches on the outer half. If this rotation wants to be successful, they are going to need to utilize the inner half of the plate more frequently, and get that first pitch strike at a much higher rate.

The advanced metrics show that their rotation hasn't been that bad, but they still haven't been that great. A rotation full of starters who are susceptible to the big inning is a rather concerning trait for a team with World Series aspirations. With injuries to Christian Vazquez and Ryan Hanigan, the Red Sox were in dire need of a catcher and thus were required to call up Blake Swihart. Due to injuries, the likelihood of the Red Sox sending Swihart for a guy like Hamels doesn't seem realistic at this time, and the Red Sox may just look to their own system if they need pitching help. Luckily for them, they have a few talented prospects in Henry Owens, Eduardo Rodriguez, and Brian Johnson who could be key players for the Red Sox this season.

All statistics courtesy of Brooks Baseball, FanGraphs, and Baseball Reference.

Brandon Decker is a contributor at Beyond the Box Score as well as BP Wrigleyville. You can find him on Twitter @bdeck02.