Sidelined by a head injury since mid-September of last year, veteran D.C. United defender Bryan Namoff called time on his battle to return to the field, announcing the suspension of his career to join the United staff.

“I’m retiring/suspending my career because of injuries,” said Namoff on Twitter. “This has been the most difficult time I’ve ever had to face. Thx to all for the support.”

Namoff, 31, never played a minute this season in what would have been his tenth in Major League Soccer, all of which have been spent in Washington. He had one of his best campaigns in 2009, with two goals and four assists in 26 matches (2,326 minutes played). He scored the most memorable goal of his career with a diving near-post header on a corner kick against Colorado in July.

Namoff started at least 24 games in each of the past four seasons, nailing down his spot at right back during United’s MLS Cup-winning campaign in 2004.

He will join the D.C. technical staff as a special projects manager, participating in scouting, youth development and camp programming.