Closer Koji Uehara — 2-1, 2.08 ERA, 0.69 WHIP, 10 SV (1 BLSV), 13 IP, 7 H (2 HR), 15 K/2 BB 

After early-season worries, Koji Uehara has been his old reliable self in 2015. His splitter is as devastating as ever, and he's been using his fastball more at the behest of the organization. His heater has shown increased velocity, consistently around 88 miles mph in recent appearances, and Uehara has relied on it more to set up his splitter rather than merely mixing it in.  

 

Setup Man Junichi Tazawa — 0-1, 1.42 ERA, 0.89 WHIP, 8 HLD, 19 IP, 13 H (3 HR), 18 K/4 BB  

Junichi Tazawa has made the eighth inning seemingly a foregone conclusion the same way that Uehara has anchored the ninth. His slider has been unhittable to complement his heavy dose of fastballs, and he's making a strong bid to earn closer duties whenever Uehara calls it a career. The only earned runs he's surrendered this year have come on three solo home runs. 

 

RHP Alexi Ogando — 1-0, 3.18 ERA, 1.06 WHIP, 3 HLD, 17 IP, 13 H (3 HR), 14 K/5 BB  

LHP Tommy Layne — 0-1, 3.00 ERA, 1.25 WHIP, 1 HLD, 12 IP, 9 H (0 HR) 8 K/6 BB

LHP Craig Breslow — 0-0, 3.63 ERA, 1.33 WHIP, 0 HLD, 17.1 IP, 16 H (3 HR) 15 K/7 BB

RHP Matt Barnes — 2-0, 1.08 ERA, 1.44 WHIP, 0 HLD, 8.1 IP, 9 H (0 HR) 5 K/3 BB

The rest of the Boston pen gets lumped together here. Alexi Ogando has proved to be a worthwhile gamble who has staked claim to a seventh-inning role. Tommy Layne has exceeded expectations as a left-handed specialist. Craig Breslow has rebounded well from a forgettable 2014 and gives John Farrell a second lefty to employee should he burn Layne in a mid-inning jam.

And finally Matt Barnes has adapted well in his transition to the bullpen. He has seen the benefit of increased velocity and has the flexibility to pitch over an inning should a starter need to hit the showers early. 

 

Grade: A-

 

Note: Stats are courtesy of Baseball-Reference.com or FanGraphs, unless otherwise noted. All prospect rankings courtesy of BaseballAmerica.com.