i know you know this but he can make a 3rd pickoff attempt. he just has to get the runner out or it's considered a balk. i actually saw this happen a couple weeks ago in a AA MiLB game. dude took a huge lead and was nailed on the 3rd pick off attempt.
as much as i've been down on Gruesome, i totally understand why they wanted him when you look at what he had done in AA and AAA. but as we all know, success in AAA doesn't always translate into success in MLB. see Dalbek, Bobby.