There was some angst in the game day thread over Rhodes being left in to face Casilla, who was hitting righthanded, but Casilla is a switch-hitter and the right side is his weaker side, and the alternative would have been to bring in Yoshinori Tateyama, who is also going to have big platoon splits, to face Casilla.*
* The best option probably would have been to get Neftali Feliz up once Mark Lowe got in trouble, and bring Feliz in to face Casilla, and then pitch the 10th. However, it was not a "save situation," and Feliz is the "closer," so that wasn't going to happen.
Rhodes was signed this offseason to a one year, $3.9 million deal with an option for 2012 at $4 million that vests if Rhodes ends the season with at least 60 appearances and isn't on the disabled list at season's end. At this point, that deal is looking like a bad signing, with the one redeeming feature being that Rhodes isn't likely to pitch enough the rest of the way for the option to vest.
The stats are ugly for Rhodes. He has his lowest K rate since 1991, his rookie year, and his highest HR rate ever. He has a 5.65 ERA, a 6.29 FIP, and a 4.57 xFIP, none of which are acceptable for a reliever. And last season, Rhodes, after a great first half, was mediocre in the second half, meaning that we are coming up on a full year of sub-par performance for Rhodes.
Rhodes has appeared in 20 games thusfar, and has pitched just 14 1/3 innings. Only the LOOGY-est of the LOOGYs are going to have such a low IP:G ratio, and despite being signed to a big deal in the expectation he would be a legit setup man, Rhodes has moved into more of a LOOGY role.
However, he's not pitching well enough against lefties to be an effective LOOGY. He has a 5.19 FIP and a 5.12 xFIP against lefties, striking out 6.75 batters per 9, walking 5.4 and allowing 1.35 HR/9. His K and walk rates are better against righthanders, but he's allowed home runs to 3 of the 37 righthanded hitters he's faced, meaning his FIP against righties is 7.24.
One could argue that his delta between his FIP and xFIP suggests that he's unlucky...of course, he could also just be very hittable right now. His swinging strike percentage is down to 4.8% on the year, which supports the "he's hittable" theory...Rhodes just can't throw the ball past hitters right now.
FanGraphs indicates that his fastball, slider and changeup are all down over two mph from last season. His fastball is coming in at 89.2 mph -- from 2002-2010, his lowest average fastball velocity was 91.3, last season. His lowest slider velocity was 81.4, in 2006. The numbers correspond with what our eyes are telling us -- Rhodes' stuff just isn't there anymore.
There's a lot of "let's just cut him" talk among fans, but the problem is that you aren't rife with better options right now. Neither Darren Oliver nor Michael Kirkman are really suited for a LOOGY role, and there's no one beating down the door in the minors who is a fit for that role (or, for that matter, who is beating down the door for a job in the bullpen). I think it makes sense to ride things out with Rhodes for a little while longer.
But the reality is, the Rangers signed a pitcher who turns 42 this year. Every old player eventually is done, and the older they are when that happens, the faster they fall apart. At this point, I think it is more likely than not that the Rangers bet that Rhodes another year or two left in his arm has come up snake eyes.