UPDATE Tuesday, 1:57 pm ET: Joseph Mora has undergone successful surgery to repair a broken jaw, sustained a concussion and will enter concussion protocol, D.C. United announced Tuesday.
The club added he is expected to return to training in four weeks.
Mora exited D.C.'s 2-1 win over Orlando City SC in the first half after a nasty collision in which he took an inadvertent knee to the face. There is no timetable for his return yet.
The 26-year-old joined D.C. from Costa Rican side Saprissa at the beginning of last season and quickly became an integral member of United's lineup, making 30 appearances in 2018. He started each of D.C.'s four games this season as the club kept clean sheets across the first three.
Chris McCann replaced Mora on Sunday and could expect to see an uptick in minutes moving forward.