Josh McEachran has suffered an injury setback after a second scan on his ankle injury has shown ligament damage.
The Brentford midfielder suffered the blow at Sheffield Wednesday in February and has been absent ever since.
The hope was he'd be back before the international break but, after a second scan, it appears that McEachran could even miss games with Bristol City, Leeds and Cardiff.
Smith said: “He had to rescan his ankle and there was a ligament injury so it's held him back a little bit but we're hoping he'll be back training after the international break.
“Fitness wise, we'll have an idea when he starts training because we have three games in a week with Bristol City, Leeds and Cardiff. We need to get him back on the pitch as soon as possible.”
Nico Yennaris appeared to be struggling with his calf injury on Tuesday night against Wolves and Smith will leave it up to the medical department as to whether they want to shut him down after the Bees secure a fourth straight season in the Championship.
He added: “Nico, as we all know, has had the injury for a long time. Sometimes he's stretching it after five minutes and after 45 minutes.
“He wasn't stretching it until after half an hour on Tuesday. The one things he's got is a drive to get through things. He'll hold his hands up and know he wasn't at his full potential.
“It's down to the medical department (whether he goes for an op). They're nursing him through games and managing his minutes.
“He's not getting the training minutes to allow him to be ready for games.”
Smith confirmed: “Alan McCormack comes back into the squad. He got 45 minutes in the B team game.
“It probably comes a bit too soon for Andreas but he won't get into the squad for this weekend but he's been called up by Denmark and he can work back to fitness with them.
“Lasse Vibe has been called up for Denmark. Rico Henry has been called up for the 20s and Ellery Balcombe has been called up.
“We've got a few internationals here at the moment. It shows the profile the club is in now and the players we've got.”