Sunday's planned farewell for Rangers pair Stefan Klos and Dado Prso at Ibrox is in jeopardy.
Klos has featured just twice for Rangers this season
Manager Walter Smith aims to field both men in the final home league match of the season against Kilmarnock.
But keeper Klos is doubtful with a dislocated thumb, while striker Prso is recovering from tonsillitis.
Smith told Rangers World: "We hope to give a show to both Stefan Klos and Dado Prso in the final game because they have both been great servants."
The 35-year-old Klos, who will retire at the end of the campaign, moved to Ibrox from Borussia Dortmund in 1998.
But injuries have limited the German to just five appearances in the last two seasons and he has once again hurt himself in training.
"Stefan dislocated his thumb in training last Friday and that meant he couldn't be involved in the Celtic game," said Smith.
"We will have to see how that clears up but we hope that it would be all right to enable him to have some of the action."
Croatian international Prso, 32, has spent three seasons at Ibrox and intends to move on to a less intense environment, due to a troublesome knee injury.