

(L.A. Galaxy photo)

With Jeff Parke sidelined indefinitely with migraine headaches, D.C. United addressed depth in central defense Tuesday by acquiring second-year pro Kofi Opare from the Los Angeles Galaxy.

In exchange, United agreed to swap positions in MLS’s allocation order, which is used when some U.S. national team players sign with the league. The Galaxy is now third on the list, while United drops to 11th. D.C. also received a second-round pick in the 2015 MLS draft.

“This is an important move for us to make at this time to add depth to our squad as we enter the second half of the MLS season and the CONCACAF Champions League group stage,” United General Manager Dave Kasper said in a written statement.

United, second in the Eastern Conference, is heading into its busiest stretch of the campaign: eight matches in 33 days, including the CONCACAF opener against Jamaican club Waterhouse in late August.

Opare, 23, has appeared in six league matches this season, with five starts. Since the Galaxy drafted him in the 2013 second round from the University of Michigan, he has played in 12 regular season games and started 11.

“This is a move that gives us the necessary flexibility to strengthen our roster,” Galaxy Coach Bruce Arena said in a written statement. It is unclear who the Galaxy is targeting before MLS’s international transfer window closes Aug. 6.

Opare ($48,500 base salary) fills a roster void left by Parke, who missed a month with a foot injury and then was sidelined with migraines. Rookie Steve Birnbaum has performed well starting in Parke’s absence, partnering with captain Bobby Boswell. Birnbaum is expected to remain in the lineup. Opare joins Nana Attakora as the primary reserve center backs.

Opare was born in Ghana and is eligible to play for the U.S., Canada (where he was raised) and Ghana. He has played for the U.S. under-20 national team.