Washington says Olt is going to play everyday against lefthanded starters, either at first base or designated hitter. Olt is apparently also going to spell Adrian Beltre at third base from time to time when Beltre DHs or gets a day off, and could play some against righthanded pitchers.
As I mentioned earlier today, my guess is Olt's playing time against righthanders will be dictated by how well he plays overall. If he hits well when he gets playing time, he'll play more often. If he doesn't hit well when he gets playing time, he'll be relegated to a platoon role.
I do think it is noteworthy that Ron Washington is saying that Olt will get his "fair share of playing time," and will be starting against lefties, as I think that's more than he ever committed to with Brandon Snyder. I also think, as I've previously stated, that I don't think the Rangers would have called Olt up if was only going to be used as often as Snyder and Leonys Martin were used.