After the injury problems that slowed him down last year, it's looking like he's 100% recovered.
For somebody off to as hot of a start as he is, it's a fine balancing act between "sell very high" or "don't sell at all".
He seriously could have an MVP season this year, hitting behind Granderson, Polanco, and Sheff with Guillen and Pudge protecting him. Maybe it's the Detroit-homer in me, but I genuinely don't think I could trade him right now, for almost anybody. He shows no signs of cooling off anytime soon.
If you're looking to sell him high, you'd better be getting TOP dollar at this point, because we're not talking about a B.J. Upton here, who's average is going to drop by 75 points and RBIs dry up. We're talking about a guy who could possibly keep this pace up all the way through a pennant chase.
Besides, even if he did drop back down to his "normal" production, he's still a top 10-15 Outfielder, so it's not like you're risking anything by holding on to him. The only risk involved is that of re-injury, which is the same with anybody.
I think if you were lucky enough to snag him before this month, you'd better just thank your lucky stars and ride his comet out through the season. If you weren't lucky enough to be on-board, you definitely can't afford to buy a ticket now.