Syers sustained an ankle injury during the first half of Rovers' 2-0 defeat at Bury last Saturday and had to be substituted seven minutes into the second half.
The club are still waiting to discover the extent of the problem.
Fellow midfielder Martin Woods might be back in contention against the Saddlers after remaining on the sidelines at Gigg Lane.
Woods has been out since November with a thigh injury but completed 50 minutes in a practice game at Manchester United 11 days ago.
Boss Brian Flynn, who this week appointed David Williams as his assistant, insists he knows his starting XI but admits he has a selection dilemma when it comes to filling the bench.
"I'm in a great position because I've not got problems picking the team, I've got problems picking the substitutes," said Flynn. "That's even better - it makes it a strong squad.
"(QPR manager) Harry Redknapp had to put two goalkeepers on the bench the other week, just to fill it up. It can be difficult at all levels but not for me."
The likes of Robbie Blake, James Husband and Jordan Ball will be looking to get back into Flynn's squad after being overlooked last weekend.
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