Or Marwin, whom he'd also used as a pinch runner, although he is just a smidge faster than Dominguez. Corporon was also available, as was Guzman.
I don't know the last time Singleton got a hit, but his ABs are far, far superior to Grossman's, IMO. He might have some swing and miss, but he is generally swinging when he should, and laying off the crap.
And to belabor a point, Swinger has to learn that not every swing needs to be for the left field fence. I wonder if that is even communicated to him. Maybe I'm unaware of some SABR truth.