C.J. Wilson, Rangers: The Rangers' Akinori Otsuka is often mentioned as the team's best reliever, but not so. Joaquin Benoit has a 118 Base Performance Value (BPV), Wilson has a 103 BPV, while Otsuka has a 83 BPV. Wilson and Otsuka are extreme ground ball pitchers -- both have a 25 percent fly ball rate. Benoit has a more standard 39 percent fly ball rate, but a better strikeout rate and K/BB than either of them, and a better walk rate than Wilson by a wide margin. All three have an actual ERA in the 2.00s, which is some feat in that park.
Wilson appears to be solidifying his hold on the closer's role. The problem is, Wilson's history, particularly with split values suited to specialty work, may be his undoing. If you're speculating for short-term saves, Wilson is your man. He could lose the job in less than a week, but so far, he has been the Rangers' closer. If you can roster Joaquin Benoit, he would be a decent reliever to handcuff to Wilson, but make sure that you can afford two Texas relievers on your ERA/WHIP.
Matt Guerrier, Twins: Continuing the search for safe ERA/WHIP relievers, Guerrier is a nice right-hander with a 6.3 K/9, 2.9 K/BB, 0.4 HR/9, 87 BPV and 3.58 Expected ERA (xERA) in support of a 1.71 actual ERA. The sparkling actual ERA has a lot to do with his 48 percent ground ball rate. Guerrier is not in a role that leads to vulture win chances, but his ERA/WHIP potential remains a solid bet over the next six weeks.