Polanco can take his time getting back as far as I'm concerned. I'd much rather go with Bliss for now. Small sample size, but so far he's been a far better defender, a difference maker as a base runner, and he's doing fine at the plate for a guy with only 30 major league AB's.
As far as Geno is concerned, we really don't need another guy that's struggling, and just hoping that a change of scenery will help him get back on track. Rojas has done a very good job at 3rd and although he's cooled off quite a bit after a hot March/April, he's still above average against right handed pitching. Unfortunately, he's been awful against lefty's though, (which isn't uncommon for left handed hitters), so probably should switch him out against left handed starting pitching.