Aberdeen winger Jonny Hayes spent the night in hospital after sustaining a head knock in the Scottish League Cup tie against Alloa Athletic.
The 26-year-old was stretchered off in the second half following a clash of heads with Alloa's Daryll Meggatt.
The Dons won on penalties after the match finished 0-0 after extra-time.
Willo Flood was also substituted for the hosts and both players are considered doubts for Saturday's meeting with St Johnstone.
However, Josh Magennis is expected to recover from a shoulder knock that ruled him out of the tie against the Wasps.
"Hopefully the two boys aren't too seriously hurt," said Aberdeen manager Derek McInnes.
"Willo's hamstring went, and with Jonny I don't think it's anything too serious but obviously it's serious enough.
"We were battered and bruised a wee bit, but we got through the tie and I'm delighted with every single one of my players."