I'll just list the Tigers since that's what I know:
SP Robbie Ray (AAA): Will get his first ML start tomorrow at home vs Houston which should be a decent match-up for him. He'll end up pitching a game before Doug Fister does this year, but he won't be sticking around very long. He's got a 1.53 ERA, 1.13 WHIP, 4/1 K/BB ratio and he's only allowed one homer in 30 innings. Short term he's the team's #6 starter, next year he'll have a shot at the rotation with the possible exodus of Max. Dombrowski says he's a #3 pitcher "at least," but a strong year in AAA while getting a handful of major league starts will help him. Definitely a deep keeper and dynasty play with results coming within two years. Definitely worth a look tomorrow if you need a fill.
OF Ezequiel Carrera (AAA): Known in fantasy circles for his energy bursts, he's a rosterable player in deep mixed leagues and AL only if and when he gets a call. With Andy Dirks still out another month, any injuries to Tiger OFers will result in Carrera getting a call. He's got a .380 OBP and 6 steals in Toledo.
C James McCann (AAA): He's going to be a terrific defensive catcher, skilled at handling pitchers, throwing out baserunners, and minimizing passed balls. He is starting to hit for average and while there is some power potential, it hasn't yet been harnessed. Not any kind of fantasy option but he could be a good backup SIM league catcher as soon as next year.
SS Eugenio Suarez (AA): Slick fielding SS has shown some power this year with a .530 slugging so far and he's always been a walk machine. Some consistency here will earn him a promotion to Toledo soon, and he could be in the mix for major league at bats later this summer. Starter upside with his glove and pop, could have dynasty interest at some point.
RP Cory Knebel (AA): Tigers first round pick a year ago, he's got 57ks and a .89 WHIP in 41 minor league innings. He's got a high 90s fastball, a plus curve and he has pretty much over-matched hitters at low A and AA. He's a college kid who closed three years at Texas and you might actually see this arm later this year in Detroit. Projects as a set-up man and closer but has some work to do with his control. Definitely a dynasty guy to keep on the radar.
Not quite on radar yet: SP Jake Thompson (A+), SP Johnathan Crawford (A+), and OF Steven Moya (AA). Those guys are not destined for Detroit until 2016 although Moya could move quicker because he's got intriguing power, but probably nothing to see here until later. 2B Devon Travis (AA) probably also worth mentioning as a possible future starter with the big club, but he's still figuring out AA at the moment. He has been an absolute monster through high A though.
Graduated: 3B Nick Castellanos, I'm sure you already know him but he's going to be very good.