The Minnesota Twins spent $800,000 to sign outfielder Max Kepler out of Germany back in 2009. This was a record bonus at the time for a European hitter. Kepler hit well in rookie ball but was just slightly above-average upon reaching full-season ball in 2013, hitting .237/.312/.424 (wRC+105) for Cedar Rapids in the Low-A Midwest League. Moved up to High-A Fort Myers in 2014, he improved a bit to .264/.333/.393, wRC+109.
Here's the comment from the 2015 Baseball Prospect Book, laying out Kepler's status entering 2015:
Everyone keeps waiting for Max Kepler to break out and it keeps not-quite happening. Not that he’s been bad: his production has been consistently slightly above-average in context, including a 109 wRC+ in ‘14. You see him on the right day and you’ll find a guy with a nice-looking swing who can pull the ball for power or work the opposite field gap for base hits. He’s also refined his glovework and played well in center field last year after struggling enough in ’13 to prompt worries about a move to first base. On the other hand, he still has trouble with left-handed pitching, and his distance power remains more theoretical than actual. On the third hand, he’s still just 21 (22 in February) and his European background makes it more likely that his growth curve could be unusual. Grade C+.
It looks like that breakout is finally happening.
Through 49 games at Double-A Chattanooga, Kepler is hitting .331/.393/.530, wRC+164, with 17 doubles, five triples, three homers, nine steals in 12 attempts, and a 19/23 BB/K in 181 at-bats. He's been tremendously hot lately, hitting .485 in his last 10 games including four-hit nights on June 15th and June 17th. He's not having any trouble with left-handed pitching right now, hitting .325/.378/.450 against southpaws.
On defense, he's split his time between all three outfield positions and looks capable everywhere, at least in terms of range. His arm isn't very strong and right field might not be ideal as a result, but his fielding instincts are good, he's reliable, and is maintaining his range. Worries about a shift to first base have subsided.
While Byron Buxton is (deservedly) getting all the attention right now among Twins outfield prospects, Kepler shouldn't be overlooked and appears capable of becoming a regular outfielder himself.