Hamdan Al Kamali, the UAE defender, has been ruled out for at least four weeks with a fractured cheek bone.
He will miss tomorrow's World Cup qualifier in Lebanon and the Olympic team's first qualifying match for London 2012 against Australia.
Al Kamali, the Olympic team captain, suffered the injury in the closing moments of Friday's 3-2 defeat to Kuwait in Al Ain, when he was sent up front by Srecko Katanec, the coach, as the UAE searched for an equaliser.
The Al Wahda defender went up for a set piece and was struck in the face by a Kuwait player when he went for a high ball. He went down immediately and was later carried off the pitch on a stretcher.
His injury was a double blow for the UAE, who lost their first match of the 2014 World Cup Asia Zone third qualifying round. It leaves them with an uphill struggle to qualify as one of the top two teams from Group B.
South Korea and Kuwait lead the way after one game and the UAE's match against Lebanon, expected to be the whipping boys of the group, is a must win game. The Lebanon lost their opener against the Koreans 6-0.
Al Kamali underwent surgery yesterday and his place in the side that travelled to Lebanon is now filled by Fares Juma, the Al Ain defender.
"Hamdan underwent surgery for a broken cheek bone at the Al Noor Hospital in Al Ain and will be out of action for more than four weeks," Jaseb Majeed, the FA's media manager, said.
Al Kamali will be a major absence for the Olympic team when they travel to Australia for their opening match in the third round of qualifiers for London 2012, on September 21. He was to join up with the team after his duties with the senior side. The Olympic team fly to Australia on Friday.