Livingston's Marvin Bartley reckons Odsonne Edouard "didn't look invested in Celtic" during his side's 2-0 win over St Johnstone.
Edouard was substituted in Perth as his side were held by the hosts before two late strikes from Neil Lennon 's substitute forwards Leigh Griffiths and Patryk Klimala.
The French striker started the Premiership season with a hat-trick against Hamilton but hasn't recaptured his best form since a niggling thigh injury.
Commenting as a pundit on BBC's Sportscene, Bartley said: "He's set such high standards and, he didn't seem himself today, he didn't look fully invested in actually being at Celtic.
"We see some clips here and the ball is going into him, he gets on the half-turn, first bit is so, so good and then his touch lets him down when he tries to drive forward.
"So unlike him. Again, Frimpong gets the ball down the right-hand side, he comes in to show, he's flicking at things.
"Even his reaction to losing the ball...in the 60th minute he's taken off and he can't really argue. I think Celtic, obviously the window closes tomorrow, hopefully from their point of view he's still there on Tuesday morning and hopefully he can kick on from there on in."
While Bartley wasn't enamoured with Edouard's performance, he was complimentary to team-mate Klimala.
The Pole climbed off the bench to add the late second against Saints and the Livi captain believes his attitude was night and day compared to his fellow striker.
Bartley added: "He's making an impact whenever he can, he's probably disappointed he's not played more games or started more games.
"This is someone who wants to make a difference and I spoke about Edouard not being invested, this is a man who definitely is, and he wants to show the management team and the fans that he can step up."
