Here is what the site--prospect report.com has to say about Hummel from a few days ago
4. TIM HUMMEL (3B) - DOB: 11/18/78 - ETA: 2004
(Triple A - 388 AB, .294/.362/.464) Hummel has bounced back from a mediocre 2002 with a very good performance in AAA-Charlotte. He's played second base and shortstop, but has spent the majority of his time at third base. There's no reason to think he couldn't put up Ty Wigginton-like numbers, or very possibly - better.
It would appear that he has enough arm strength after all to play the hot corner...