I think it all depends on the 2nd half of the season. I've always liked Pronk, but he needs to show that he can produce for at least a couple of months when we need him, and without getting hurt. If he can't, then they should just probably forget it.
We have already been paying the price for the Sizemore blunder, and as you stated, the fact that he can't take the field is a killer. We kind of got lucky this year with his latest injury coming during most of the interleague play, when he wouldn't have been in there anyways... Last year though, it killed us, and it would kill us in the WS if he was hitting.
I would almost rather see them have Sizemore completely shut down this year, which may be the case anyways. (they have been pretty mum about him lately.) Then, take a look at both Sizemore and Hafner, and maybe choose just one to take a chance on with a very cheap contract filled with incentives, and let the other one walk. I would prefer it be Sizemore, if he is ever able to play again. (He could DH, and then play limited OF.)
And, I also agree with you about Laporta. I feel that he would have had better numbers than a lot players on this team so far, but that ship has sailed.