From this article, it looks like his mechanics are improving, but his velocity is down in the low-to-mid 90s. This was also an issue at this time last year.
bad move.
but you can still come out of this with the upper hand. If Cain starts out as bad as he did last year, than try to get him back. He'll be money down the strech, while Bonderman always seems to start the season as the greatest pitcher ever lived than collapses in the second half.
So unless you are attached to Bonderman do that trade around mid june.
As for Jenks, I think he had some arm discomfort in early March, but since then, he has been fine.
I wouldn't worry too much about him though. He's a power pitcher and he'll get his stuff together for the regular season. Unless MacDougal performs REALLY well, his job is safe.