Nicolas Gaitan was taken to hospital as a precaution after being knocked out during Dalian Yifang's 3-0 defeat at the hands of Beijing Guoan on Friday as last season's second-division champions continued their woeful start to the new Chinese Super League campaign.
Gaitan dropped heavily to the ground in the 56th minute with Dalian trailing by two first half goals after being caught by Li Lei's flailing elbow as the Beijing defender was tracking back at pace.
"There was some minor concussion for Gaitan," Dalian boss Ma Lin said of the former Benfica winger, who was signed from Atletico Madrid in February.
"At the time there was some memory loss. He has already gone to hospital for an examination and we don't have any results yet."
Gaitan missed the final 34 minutes of Dalian's third defeat in a row as Jonathan Soriano scored a brace while Wei Shihao was also on target as Beijing Guoan underlined the difficulties last season's China League One champions are facing in the top flight.
Jose Fonte hit the crossbar with an early header for Dalian but Beijing went in front in the 12th minute when Wei Shihao was awarded a penalty and Soriano stepped up to give Guoan the lead from the spot.
Wei doubled the advantage 12 minutes later when he raced on to Renato Augusto's reverse pass before wrapping his right foot around the ball and curling his shot beyond goalkeeper Zhang Chong.
And just after the hour mark Soriano claimed his second to give Beijing a comfortable cushion as Dalian conceded their 13th goal in just three games.
"As head coach I have to say sorry to the fans and bear much of the responsibility," said Ma, whose team had lost to Shanghai SIPG and Guangzhou R&F before the defeat against Beijing. "We played poorly and the team's performance was not good."
Beijing now have six points from their opening three games as Roger Schmidt's side notched up back-to-back wins following their opening day loss against Shandong Luneng.