I have used M. Cabrera before as a dh but never as a full time 3b. I believe he will hit in Petco but will I survive the errors and hits going through his legs?
There is no reason why it can not work, if you are solid elsewhere defensively, and have good pitching. One bad defender at a corner position can not derail a good(or lucky) team! Good luck.
Obviously both Neil and I had Cabrera going at big time HR stadiums, so Miggy's offensive stats are much more impressive than they would be at Petco, but I was fortunate enough to play a whole season with Cabrera and have him only commit 10 miscues.