Barry Robson and Tony Mowbray have offered their support to under-fire frontman Marc-Antoine Fortune.
Celtic shelled out £3.8million in order to take the burly forward from Nancy over the summer, but have seen his progress in Scotland hampered by injury.
A knee problem picked up during the early stages of the 2009/10 campaign kept the 28-year-old sidelined for two months.
He has started each of the Hoops' last three fixtures since returning to full fitness, but it is yet to win over a sceptical fan base.
Fortune was jeered by the away support during Celtic's 2-1 defeat at Dundee United on Sunday, before finally being replaced by Georgios Samaras just before the hour mark.
Robson feels the treatment dished out from the terraces was overly harsh, with the Scotland international all too aware of how difficult it can be to find form after a lengthy spell on the treatment table - having only recently returned to action himself after eight months out with a groin injury.
"It's not easy, Marco is coming back from injury, as am I, and it just doesn't happen like that," said the combative midfielder.
"It's hard and I know how Marco feels because I'm not 100 per cent myself.
"But when you are at a club like Celtic you just have to try and ignore that and make sure you are at your best.
"You need to make sure that you get goals and Marco will keep trying and do a good job for us."
Celtic boss Mowbray has also leapt to the defence of his summer signing, believing the Frenchman will come good in time.
"Fortune has had 10 weeks out," he said.
"If you know anything about football, injuries knock the confidence of footballers and he needs to get himself back up to speed.
"It's going to take time, you can't just do that with just training.
"It's going to take games and that's why he is getting some minutes on the pitch at the moment.
"But I have every confidence in him. Once he is up and running he will be fine."