There are a number of answers to the question above. You could go with "the Tigers second pick in last year's draft" or "the last pick in the supplemental first round last year" or "the first guy from the 2013 draft class to reach the majors." You could even toe the line and just say "the newest member of the Tigers bullpen," which is the most accurate and obvious answer. You should probably not go with "the newest member of my fantasy team."
Knebel is a power-armed reliever, the kind that can move quickly through a farm system. The former University of Texas Longhorn closer, Knebel used his mid-90's fastball and plus curveball to carve up hitters at three minor league levels over the past nine months. Knebel leaves the minors behind having fanned an impressive 12.2 batters per nine innings.
Relievers are able to move more quickly through a minor league system than almost any other role of player because of the limited skill set needed to work at the position. Relievers don't need to do a lot of things well, they just need to do a few things very well. Knebel does exactly that, with two plus pitches already, both of which can get even better with improved command. A lack of fastball command can derail even the most potent arm, but high velocity and a big time breaking ball makes the margin for error bigger than it would be for an average pitcher.
Knebel was also aided by the new signing date for draft picks, which was moved up earlier in the summer a few years ago, keeping players from waiting until mid-August to sign and getting them on the field sooner. Because of this Knebel was able to throw 31 innings last season, giving him almost an entire extra year of experience that he wouldn't have had a few years ago.
Knebel has the profile to pitch in the late innings and will probably be a closer at some point. Barring an injury to Joe Nathan and probably a few others, that won't be this year, but Knebel does have a chance to help in the Tigers bullpen immediately.