Jim Duffy said on BBC Radio Scotland that out-of-favour Celtic hitman Leigh Griffiths was not the picture of enthusiasm during his warming down session after Sunday's 2-2 draw with Hibernian.
The 27-year-old striker was unused substitution for the third successive game.
But it appears as if it's not only Moussa Dembele who is keeping him out of the side, but also Odsonne Edouard, who bagged a hat-trick in the 5-1 thumping of Motherwell earlier this month.
"The biggest conundrum for me is still where do you put Leigh Griffiths?" Duffy said on BBC Radio Scotland. "He didn't even get on the pitch today.
"He was doing the little runs after the game with the subs and he did not look too enthusiastic. So there's a few decisions to be made over the next few weeks."
With January just around the corner, it wouldn't be a surprise if Griffiths's situation led to speculation about a mid-season exit.
He is a brilliant goalscorer who netted 40 times during the 2015-16 season under Ronny Deila and it will be interesting to see if Brendan Rodgers lets him leave.