There's room for a left handed hitter vs. southpaws given the Twins current roster. Some of the right handed options aren't very good--Castro has hit better left handed since coming to the Twins, Bride has pretty severe reverse splits and Vásquez can't hit anybody. For now, Larnach is getting PAs against lefties. I was surprised to see him hit in the eighth inning yesterday (tie game, one out, two runners on).
When Matt Wallner returns, he might get the chances that Larnach is getting. SSS, but he's 3-5 with a homer against same sided pitchers. Of course, by the time Wallner returns someone else will probably be on the IL.
Regardless, by and large Baldelli has abandoned the early pinch hitting for left handed hitters, and I totally agree with that change of strategy. Resting Wallner and/or Larnach against left handed starters is prudent IMHO, but giving them PAs against left handed middle relievers helps later in games and later in their careers.