A Union team official said Sunday that X-rays were negative on the left shoulder of forward Danny Mwanga, who was injured in Saturday's 1-0 win over the Chicago Fire at PPL Park.
Mwanga, who has enjoyed a strong rookie season with seven goals and four assists, was hurt in the first minute but played until leaving the game in the 55th minute.
Afterward, he said his shoulder was sore.
According to the Union, Mwanga is questionable for Wednesday's game in San Jose against the Earthquakes.