I don't think he's damaged goods, but its a risk you might be able to afford with ARod in the line up, I went and looked up Alvarez on ESPN, this is what they had to say:
Alvarez (quad) has suffered a setback and is not currently playing in extended spring training games, Jenifer Langosch of MLB.com reports. Spin: There's no timetable for his return to extended spring games, which likely puts his return to the Pirates at a few weeks away.
Is there anyone else on the WW that might have more value, say Rizzo?
avilles from the royals? pishposh! for some reason the royals don't give him the playing time he deserves (and he's really kind of a platoon guy against leftys only anyway). my brother picked him up for a few weeks earlier and we got into a heated trade battle over him until we realized he didn't play enough to suit either of our needs.
i like peralta. his numbers are already going back to average for him (below elite 3rd basemen) but for the first two months he's been incredible (my everyday 3rd baseman so's i can put bautista in the OF). leeland called him "a comfortable shoe" you know you ought to throw out, but it fits so well you don't. usually 7th in the lineup, but he's in every day, less slappy than barney, but hits well for avg.with occasional power.
homer bailey is a good option when he's playing. i've used him in streaming starts, but he's no anchor for your rotation. you have a lester shields beckett chacin one two...one two....are you losing in some cat or something that you need a pitcher?
Jhonny Peralta with his SS eligibility is a nice fantasy option due to the lack of 3b production and quality SSes. There is no way I'd give him up for Homer Bailey. Sorry.
You have the best option already on your team.
Aviles better than Peralta not a chance friend not even close Aviles isn't worth rostering right now. Johnson is middling low end option. Freese is intriguing for sure in that St. Louis stacked lineup (berk/pujols/rasmus/holliday) etc.