Ipswich survived 11 minutes of added time to record a 1-0 over Bristol City at Ashton Gate.
Visiting boss Paul Jewell said: "Grant has been taken straight to hospital suffering from concussion. He was unconscious when our medical staff reached him on the pitch, but seemed okay by the time he got back to the dressing room.
"We are hoping it's not a serious injury but we will probably know more tomorrow."
Ipswich scored the winner in the second half after they had been reduced to 10 men on 28 minutes when midfielder Lee Martin was red-carded for a lunging challenge on Kalifa Cisse.
Jewell said: "I didn't get a great view of Lee's challenge, but tackling is not his strong point and if it was mistimed I know it wouldn't have been malicious. I thought the ref had a good game and we will take whatever punishment is meted out.
"On a hot day our 10 men worked their socks off. We seemed to win every ball that came into our box and if it dropped loose someone always got a block in.
"I'm not giving any thought to the play-offs because with so few games left it is still a huge ask for us to reach the top six.
"Our next game is a massive local derby against Norwich and we're all looking forward to it. I'm not thinking about anything but that match."
City boss Keith Millen said: "I'm frustrated and angry that we didn't do better playing against 10 men for so long.
"Our final ball into the box was poor on too many occasions and when we did get chances we were not clinical enough to take them.
"When it was 11 against 11 I thought we were the better team. But Ipswich got men behind the ball in the second half, which made it difficult to break them down.
"I didn't see anything that I wasn't aware of already and my transfer plans for the summer are already in place. I know the type of players we need and things are already going on behind the scenes."