Bullpen Report: September 25, 2013

• Hope you stashed Trevor Rosenthal (for a few days, at least). The flamethrowing righty picked up his third save in as many days on Wednesday, striking out a pair against the Nationals. You don’t need me to tell you how fantastic Rosenthal has pitched this year. His 2.41 xFIP puts him seventh amongst big league relievers and that’s right where he slots in WAR-wise as well.

Rosenthal has been closing while Edward Mujica is unavailable, who has been given some time off for general fatigue. The general consensus is he’ll get the job back when healthy, but I’m not so sure. Mujica’s 3.45 xFIP isn’t bad, but is also not elite, and the Cardinals closer has seen his K% plummet from 22% in the first half of the season to 12% after the all-star break. Jeff Zimmermann sees warning flags in his latest MASH report, so, let’s just say I wouldn’t be shocked to see Rosenthal closing into October.

• Like Mujica, Chris Perez is picking a bad time to start struggling. After allowing another homer last night, Perez saw his September ERA balloon to 6.23. Couple that with his 5.73 mark and you have a pitcher who hasn’t pitched like a shutdown closer for almost two months. Looking at the underlying rates, there isn’t a whole lot that jumps out. His 25% K% over the last couple months is well above his 2013 mark and his velocity has been trending the right direction. If I’m Terry Francona, I’m not panicking given his peripherals, but with the playoffs right around the corner, Perez can ill afford any more missteps over the last few games.

• Quick hits: Kevin Gregg got a save in Chicago. You can keep playing “who gets the ninth” with Gregg and Pedro Strop, but if I’m at all concerned about ERA/WHIP, it’s not worth the potential save over the last four games. Mariano Rivera didn’t pitch today, meaning he has one more game to pitch in Yankee Stadium before his calls it quits. I bet a substantial amount of money he takes the mound tomorrow, regardless of score.
Closer Grid:

[Green light, yellow light, red light: the colors represent the volatility of the bullpen order.]