If this were 2003, I could see him put up those numbers, but unfortunately I don't think that is Chavez anymore.
I can see him improving his AVG from last year, but don't expect him to hit around .280. I'd be surprised if he reaches .275. As for the power, definitely not 30HRs, especially if he misses any time.
He was on fire until he got hurt last year. He'll hit 30+ easily if he is healthy with a decent BA.
The last time he cracked 30 dingers was 2002, and he's played the whole season 2 out of the last 4 years. He won't hit 30+ easily.
And I don't think I'm being optomistic. Those are the stats he was averaging over the last few years before his down season. He's 29, he battled injuries, and suffered some bad luck (.262 BABIP). Chavez still has a long and productive career ahead of him.