According to Adam Rubin of the NY Daily News:

Look for Argenis Reyes to be in a Mets uniform as soon as Wednesday’s game. Reyes is hitting .296 this season at Triple-A Buffalo. Obviously, he struggled late last season with the Mets, at one point enduring an 0-for-25 funk. He didn’t receive an invite to big-league camp, and there must have been something he did to irk Mets brass, because he didn’t even get borrowed once from the minor-league side for a Grapefruit League game.
Apparently we haven't seen him this year because Reyes had a gruesome injury with the Bisons this year. He required groin surgery after getting struck with a one-hop grounder while not wearing a cup.

All I can say to that is OUCH!