Celtic slumped to another embarrassing defeat in Europe on Thursday night when they were thrashed 4-1 by Sparta Prague away from home in the Czech Republic.
Defensive problems that have dogged Celtic all season came to the forefront again and the Scottish champions conceded a whopping eight goals across their two encounters with Sparta Prague.
Rough believes that Celtic manager Neil Lennon must be confounded by his side’s defensive problems as the same defenders earned accolades last season for their performances.
The former Celtic goalkeeper picked out Ajer for criticism and insisted that far from being the player who big clubs wanted in the transfer window, the Norwegian has not even looked like a defender this season.
Rough said on PLZ Soccer: “I think it’s [Celtic’s shaky defence] there for everybody to see.
“I am sure Neil Lennon will be really scratching his head as well as these were defenders last year everybody was raving about and now they can’t defend for their lives at all.
“Every one of them is culpable, particularly Ajer for me, I just can’t understand.
“This was a boy that a lot of big clubs were looking at, but his decision making is all over the place.
“He doesn’t even look like a centre-half now.”
Ajer has been linked with a host of clubs, including AC Milan, but it remains to be seen if any will make a move for him in January.