This one's easy: The Red Sox rotation had a 4.39 ERA, better only than the Orioles and Detroit Tigers in the AL. So welcome to Boston, David Price.Projection from FanGraphs:
It's not that simple. Price alone doesn't turn the Red Sox into a playoff team. They'll still need improvement from other guys in the rotation, most notably Rick Porcello, who posted a 4.92 ERA and allowed 25 home runs in 172 innings. The bullpen was just as bad as the rotation, posting a 4.24 ERA, also 13th in the AL. So new president of baseball operations Dave Dombrowski traded for closer Craig Kimbrel and setup guy Carson Smith, who had a dominant rookie season for the Mariners. With Kimbrel, Smith and Koji Uehara, the Red Sox could duplicate the late-inning dominance of teams like the Kansas City Royals and Yankees.
(This impact could be overstated, however. The Red Sox's winning percentage when leading after seven and eight innings was actually right at the MLB average. But improved bullpen depth could help facilitate more late-game comebacks.)
On the other side of the ball, the Red Sox saw Mookie Betts emerge as a star. He'll be even better in 2016. After a slow start, rookie catcher Blake Swihart showed promise in the second half, hitting .303/.353/.452. Second-year shortstop Xander Bogaerts hit .320 and is capable of adding some power and OBP to his game. That trio is the new core of the Boston offense. That leaves the veterans: Does David Ortiz have one big season left in him? Will Pablo Sandoval rebound from his minus-0.9-WAR season? Will Hanley Ramirez play first base better than he "played" left field? Is Rusney Castillo actually any good?
The FanGraphs projection system likes the Red Sox as the AL East favorite right now. Of course, the projection systems loved the Red Sox a year ago as well. But with one of the best starters in the game now heading the rotation, a dominant closer and a talented group of youngsters, the Red Sox look like the surest bet to improve in 2016. And maybe the division favorite.
Red Sox 92-70 Yankees 89-73 Blue Jays 87-75 Rays 84-78 Orioles 78-84