Prospect of the Day: Marcus Semien, INF, Chicago White Sox

If you like on-base percentage, you'll love Chicago White Sox infield prospect Marcus Semien. He moved up to Triple-A Charlotte this weekend, but he was on a tear for Double-A Birmingham before his promotion, hitting .372 in July with 29 walks in 26 games. He earned Southern League Player of the Week honors right before his promotion due to a .583 batting average and 12 walks in his last seven games for the Barons.

Semien wasn't well-known outside White Sox circles pre-season, but he's certainly getting noticed now. Let's take a look at him as today's Prospect of the Day.

Semien comes from an athletic family: his father Eric was a wide receiver at the University of California. Marcus followed family tradition and went to Berkeley, but decided to play the superior sport of baseball. He didn't play much as a freshman, hitting .197 in 27 games in 2009, but in '10 he took over a regular job in the infield, hitting .328/.389/.497 in 54 games and being mentioned as a potential early pick for 2011.

He didn't have a terrific junior year with the bat, hitting .275 and losing 100 points off his OPS, although his OBP stayed decent enough at .371 (team OBP was .353). He played well with the glove and was drafted by the White Sox in the sixth round, signing for $130,000. He hit .252/.320/.376 in 60 games for Kannapolis after signing, a credible performance for a guy jumping from college ball to full-season Class A.

Semien spent all of 2012 with Winston-Salem in the High-A Carolina League, hitting a solid .273/.364/.471 with 31 doubles, 14 homers, 11 steals, and a 55/97 K/BB in 418 at-bats. He was particularly good in the second half, hitting .290/.392/.514. I gave him a Grade C+ entering 2013, with a "Sleeper Alert" tag.

As noted, he's been very strong this season, hitting .290/.420/.483 with 15 homers, 20 steals, and an excellent 80/66 BB/K in 393 at-bats for Birmingham before his promotion to Charlotte, where he is 5-fo-14 in his first three games.

Semien is a 6-0, 190 pound right-handed hitter, born September 17, 1990. He's a good overall athlete with no weak tools, although he doesn't really have any spectacular ones, either. He's developed more power than anyone but the White Sox expected, enhanced by his superior feel for the strike zone. His running speed is a tick above average but he makes the most of it, evolving into an efficient and effective stealer (20-for-25 this year), which again is more than anyone but the White Sox thought he could do before he was drafted.

The Sox used him at all the infield positions (except first base) at Birmingham. The consensus is that he's best at second, but his arm is strong enough for third base. His range is marginal for shortstop, although that's his position so far in his first few games for Charlotte.

You have to be impressed with what Semien has done over the last year and a half; if he has a good August in Triple-A, it will become increasingly difficult for analysts to ignore his performance. If he continues to max out his skills, he could be a regular. Even if he's just a .240-.250 hitter at the major league level, his ability to draw some walks, provide some power and speed, and play multiple positions should make him an attractive asset in this era of short benches.

ADDITIONAL NOTE: You can see Semien's heat map for all of his hits at this link from mlbfarm.com.