Brandon McDonald has helped shore up D.C. United’s backline since being acquired from San Jose in June. (Ned Dishman/GETTY IMAGES)

D.C. United has signed defender Brandon McDonald to a new contract, the club announced on Tuesday. The move is seen as a major one for United, as McDonald had expressed interest in signing with a European club.

Seeking defensive depth, United acquired McDonald from the San Jose Earthquakes in June for allocation money. Since joining United, McDonald has started in all nine matches, and the club has had four shutouts over that 3-2-4 span.

In the 16 matches this season before McDonald’s arrival, United had a goal differential of minus-six. But since McDonald joined the team, United has a five-goal edge over its opponents and has given up only eight goals.

“He’s got a little nasty in him,” United Coach Ben Olsen said in admiration last month. “It was much-needed back there.”

“Brandon has quickly asserted himself into our side and has helped to solidify our backline,” General Manager Dave Kasper said in a statement released by the team. “He is a very talented central defender with a huge upside, and we are thrilled to have reached a deal to keep him at D.C. United.”

McDonald began his MLS career with the Los Angeles Galaxy in 2008. He started 54 league matches over his 2 1/2 seasons with the Earthquakes.

Per MLS and United policy, terms of the deal were not announced.