Matt Reynolds has demonstrated three things so far this year:
1) His 2014 offensive surge driven by a .400 BABIP refuses to be repeatable even in the friendly confines of Cashman Field
2) He's not any better of a SS defensively than Flores, having already given up 8 errors in 175 chances at SS this season to add to the 16 he gave up last year in 431 chances at SS.
3) He doesn't have Flores' bat, managing a career .805 OPS in Vegas compared to Flores' .903 OPS there. Matt Reynolds is just Wilmer Flores, plus .020 of OBP and minus .100 of SLG and about 10-15 dingers a season.

Cheech, on the other hand, is due his chance. He's a 21 year old former first round draft pick who is hitting .320/.375/.477 (144 wRC ) in AA with an 8.9 K%. He has nothing left to prove in AA and we spent a first round draft pick on him so there's no reason for us to have him treading water behind a guy who isn't even a natural SS. For better or worse the Mets need to figure out what they have in Cheech before 2016, especially since Wright's future is still uncertain and Flores represents the Mets' best in-house option to replace Wright if needed in 2016.

The only reason why Reynolds is playing SS instead of his natural position of 2B in AAA is because he's supposed to be the backup plan if Flores bombs or gets hurt. The problem with that is that we already have a better backup option to Reynolds in Tejada. It was fine to keep him at short getting reps on the off chance that he'd get better when there was nobody behind him in line, but now that Cheech has made a legitimate claim for a promotion it's time to move Reynolds out of the way so that we can get a natural SS up at the AAA level getting seasoned.