As I look over the Rangers roster, I note that it tilts heavily right handed. The main offensive threat from the left hand side of the plate is Josh Hamilton, who loses 79 points of OPS versus LHP pitching, shedding OBP but gaining power, with a slash line against lefties of .260/.284/.541 in 2011. For his career he loses 161 points of OPS, posting a .278/.326/.471 against lefties (he is .308/.366/.543 overall for his career).
Moreland vs RHP .266/.326/.456 vs. LHP .234/.298/.279
Murphy vs RHP .296/.348/.461 vs. LHP .215/.274/.234
The next most likely left handed batter to see playing time is Endy Chavez, who has a minimal platoon split in his career.
Both Moreland and Murphy have significant platoon splits. But neither are that fearsome with against right handers, and Moreland has seen limited playing time this postseason.
Other than Hamilton, the most dangerous hitters in the Rangers' line up are right handed. It also has little in the way of switch hitters. It seems a lineup that provides limited opportunities for a left handed short reliever.
Arthur Rhodes has been minimally effective this season, with lefties hitting .245/.344/.528 off of him, and righties managing a .288/.312/.534 line. He has, though, been reasonably effective in the postseason, facing 7 batters, walking one, allowing no hits, and striking out 3. Rhodes also is not likely to go long or eat many innings--in 51 games his year he pitched just 33 innings.
Rhodes also spent much of the season a Ranger, so I would think they are well aware of his current capabilities.
- the limited number of left handed hitters on the Rangers roster
- the only one exceptional left handed hitter in their lineup
- Rhodes' limited effectiveness against any sort of hitter this year
- Rhodes' inability to have long appearances
- The Rangers knowledge of him
Jake Westbrook, for example, can pitch multiple innings and was more effective against left handed batters this year (.260/.343/.391) than Rhodes.
I'm pretty sure the Cardinals will keep Rhodes on the roster, but I would think seriously about cutting him if I was them. The only exception would be if they have reason to believe that some other pitcher (out of Westbrook, McClellan Sanchez, and Boggs) is even less likely to be effective.