Mackay-Steven discharged from hospital
Aberdeen's assistant manager has confirmed that the player has now left hospital after being monitored following concussion.
Mackay-Steven was stretchered off during Aberdeen's 1-0 defeat to Celtic in the Scottish League Cup final on Sunday after a horrible clash of heads with Dedryck Boyata shortly before the interval.
He was taken to hospital during the remainder of the match but was released the following morning after undergoing precautionary examinations.
Aberdeen assistant boss Tony Docherty confirmed the news in a press conference on Tuesday.
He said: ""He left yesterday afternoon and considering everything he is in good spirits. He went to hospital after the game but they thought he was okay to be let out and we had two doctors at the hotel. He was sick that night when he got out of the hospital."
Docherty added: "Apart from a sore head he is making a recovery just now and it is just important that we monitor him and make sure he is okay. The medical team is keeping us advised. He has to go through certain tests to make sure he is okay for games coming up."
Mackay-Steven has been ruled out of Wednesday's league match against Rangers as a result.