What has his performance been like?
Christian Yelich was dominant at High-A last season. He hit .330 with 12 HR and 20 SB. He displayed a great approach at the plate and solid patience as evidenced by his .404 OBP. After an okay performance in the AFL many expected Yelich to spend all of 2013 at AA. Thus far he's done everything he can do speed up his ETA. Yelich turned heads in spring training by hitting .364 with 5 HR and 6:7 BB:K in 44 AB. Yelich started late at AA because of a foot injury but is hitting .306 with 6 HR and 2 SB in 108 AB since returning.
What is his current status?
Yelich doesn't have much left to prove in the minors before he is under consideration for a promotion. He may even go straight from AA to MLB just like Marcell Ozuna did. I think that the Marlins will probably wait until closer to the trade deadline to trade away Juan Pierre and go with an Ozuna-Yelich-Stanton outfield.
What can we expect moving forward?
It looks like Yelich will hit for a great batting average but I question how many SB he'll be able to produce at the MLB level. Jason mentioned that "he has the potential to be a 15-20 home run bat with a solid batting average and above average speed totals (think 25-30 steals a season) at his peak" but I am actually thinking the exact opposite. Yelich has very good HR power and should be able to hit 25-30 HR a season, even in the Marlins ballpark. I don't think he has the speed to steal more than 20 bases per season but 15+ is certainly possible. He took advantage of some low-level catchers on his way to 32 SB's in A-Ball but I don't think that A-Ball SB numbers directly translate as a player moves up the minors and into MLB because the defensive quality of catchers tends to improve dramatically. It's arguable that Yelich could have as much of an impact if not more than Oscar Taveras would if called up. Yelich will likely slot into the 2nd or 4th spot in the order whereas Taveras would likely hit 6th at best. Although Taveras would be in the better lineup he's also a long-shot to have a spot to play in St. Louis this season unless there is an injury. Taveras is already owned in most single-season leagues but Yelich is probably still available depending on your exact format. If you have the bench spot and need an impact outfielder then it's time to add him right now and speculate.