The Twins have promoted a former University of Kentucky starting pitcher to the big leagues from Class AAA Rochester, but it's probably not the one Twins fans were expecting.

Logan Darnell, teammate to star prospect Alex Meyer at UK and with the Red Wings, will join the Twins in time for tonight's series-opening game with the Orioles at Target Field, the Twins announced Friday. The 25-year-old lefthander owns a 1.69 ERA in four starts at Rochester, but he'll probably make his major-league debut out of the bullpen tonight.

To make room for Darnell, the Twins placed outfielder Aaron Hicks on the seven-day concussion list, leaving the team with a 14-man pitching staff and 11 position players for the next day or two. Oswaldo Arcia, who has missed three weeks with a sore right wrist, is expected to complete his rehab assignment soon and rejoin the team.

Hicks collided with the center field wall during Thursday's second game. He stayed in the game initially, but was removed for a pinch-hitter an inning later.

The Twins need an extra arm for the bullpen after calling upon their relief pitchers for 12 2/3 innings in Thursday's doubleheader against Los Angeles. Only two or perhaps three relievers are available to pitch today, causing the Twins to dip into their Triple-A pitching staff to get through the next couple of games.

Darnell, a sixth-round pick of the Twins in 2010, last pitched on Sunday, allowing one run over 6 1/3 innings to Charlotte.

The Twins face Baltimore tonight at 7:10 p.m., and Saturday and Sunday at 1:10 p.m., before leaving on a six-game road trip.