There was a lot of hand-wringing the first month of the season, but the bullpen has quietly cemented itself as the strength of the Sox team. They currently rank 12th overall according to FG with plenty of reasons for optimism moving forward. Some stat lines so far this season:
Jones 3.50 ERA, 3.86 FIP, 4.12 xFIP, 10 K/9, 3.5 BB/9
Soria 5.65 ERA, 3.21 FIP, 3.76 xFIP, 10.67 K/9, 1.88 BB/9
Avilan 5.25 ERA, 3.47 FIP, 4.14 xFIP, 11.25 K/9, 5.25 BB/9
Bummer 3.68 ERA, 2.39 FIP, 3.38 xFIP, 9.82 K/9, 3.68 BB/9
Rondon 3.86 ERA, 2.28 FIP, 3.55 xFIP, 11.57 K/9, 4.50 BB/9
Fry 0.00 ERA, 0.98 FIP, 2.14 xFIP, 12.96 K/9, 2.16 BB/9
You'd like to see some improvement with Avilan and Rondon's BB%, but they are both striking out a ton of people so they can get by with the elevated BB totals. In addition, Avilan and Soria are both battling BABIPs above .400 right now, so we should hopefully be seeing some positive regression on both accounts. The emergence of the last 3 is what has really surprised though. The Sox can effectively move all of their veteran talent in the bullpen this deadline, get some pieces for the system, and still have a solid core next year that they can supplement with Burdi, Hamilton, and maybe a free agent or two. Optimism!