I'm not sure how long that would take. Phelps is primarily going to DH, and with Delgado at first it doesn't seem like he'll play there much. If Delgado gets hurt, then I would have to think that Phelps would be the replacement. I think Phelps will out-produce Huff, but you're handcuffed becasue of eligibility problems. Huff will also start the year at third from what Pinella has been saying, so that helps his value. Is there anyone else you could drop to make room for Phelps? I'd try to work out a 2-for-1 deal so you'll have an empty roster spot.
I'd see what the other teams are offering for Alfonzo before you make the decision to keep him. You may get someone to overpay for him and then make another trade to get yourself a player you really want. I always try to take into consideration how other owners might value a player before I make a trade.