As we say goodbye to May and hello to June, the Buffalo Bisons continue to hang tough after losing several key players to injuries as well as major league call-ups. It’s been so bad that they’ve had to bring in a few career minor leaguers just to fill out the roster. They are just 5 games under .500, which is pretty good considering all the players they’ve lost, and contending for a playoff spot down the line isn’t out of the realm of possibility. But on to the individual prospects:Jenrry Mejia: As we all know by now, Mejia had Tommy John surgery and is done for the year. He may not make it to the big leagues again until 2013.Josh Stinson: He made 6 starts in May, and was better than he was in April in that his ERA was below 5 in those 6 starts. However, he still gave up a hit per inning, but his low walk rate kept his WHIP around an acceptable 1.3. His strikeouts are still nowhere close to where they need to be, which is why he would not be a great choice to make a spot start in the big leagues. He did pitch 6 shutout innings his last time out, so perhaps he is improving.Chris Schwinden: After breaking out in April, Schwinden has leveled off a little in May. He’s given up 5 runs in each of his last 2 outings. Based on performance he’s likely first in line for a spot start, even though he’s not the prototypical pitcher you see having success in the major leagues.D.J. Carrasco: D.J. has nothing to brag about in his may. The best way to describe his time in AAA is consistently mediocre. He hasn’t been hit hard, but he hasn’t been dominant like a major league pitcher should be in AAA. He gives up 2 or 3 runs every outing while pitching 5 or 6 innings, and had only 1 outing where he struck out more than 3. He’s easy to call up if needed, but hasn’t stood out and looked like a guy deserving of it.In the bullpen: Manny Acosta has worked through his problems with walking guys and is pitching great. In 13.1 innings in May, he struck out 21 and posted a 0.68 ERA. Since returning form the big league Ryota Igarashi has made 4 appearances and struck out 10 in 5.1 innings. He’s likely behind Acosta for a promotion, but does have the advantage of being on the 40-man roster. John Lujan has some serious heat and after struggling in AAA last year, he has been much better this year after seeing time in Binghamton. His WHIP is at 1.2, ERA is below 3 and he is averaging close to a strikeout per inning. Those numbers won’t warrant a promotion, but they are decent enough to keep an eye on, especially for a guy who throws as hard as Lujan. Taylor Tankersley had a fantastic April and has done a complete 180 in May, posting a 7.36 ERA. With Tim Byrdak and Mike O’Connor, the Mets don’t need another lefty in the bullpen anyway.Kirk Nieuwenhuis: Kirk has not played since May 24 with a shoulder injury. His numbers in May are nearly identical to April, with almost the same number of at bats. He has a few less extra-base hits and a few more strikeouts, so there is a slight regression, which doesn’t mean much. The thing that stands out about Kirk is his lefty/right splits. His average is nearly .100 points higher against righties. He has 19 extra-base hits against righties and 4 against lefties, which is something to be concerned about even though 60% of his at bats are against righties. The good news is that he’s hammering righties, but the bad news is he’s still not great against lefties, which was something he had to prove heading into the year.Fernando Martinez: He spent most of May in Queens and faired well. The talent is there, but as always he needs to stay healthy. If he does, he will be back at Citi Field sometime this year.Lucas Duda: Duda spent most of May out with a back injury, and missed a chance for a major league call-up. He has homered twice since he returned, and 5 homeruns in fewer than 100 AAA at bats is pretty good. At some point, he should be back in New York but will need to do better than 2-20.Zach Lutz: He has not played since April 21, missing a chance to play everyday in the majors. Injuries have plagued Lutz throughout his career and this most recent one was the worst because another chance to showcase his talents in the big leagues may not come around again.Michael Fisher: After starting the year in Binghamton, Fisher was promoted and has done fairly well while playing a variety of positions. He already has 3 homeruns in 18 games and is batting .292. He’s not a major prospect, but if he hits and continues to play a variety of positions, he could be a useful utility guy.Mike Nickeas: Nickeas hasn’t played much since being demoted back to AAA, so he hasn’t done much hitting. But the Mets know what they have in him, if there’s an injury he can back up in the majors, if not, he should return in September.