Bunyan has not raced since 10 April because of a knee injury
Stoke Potters skipper Jason Bunyan could return from a knee ligament injury to face Workington in the first leg of the Knockout Cup on Saturday.
"I have to make sure that I'm right to do so and I will not be taking any chances," Bunyan told the club website.
"If I come back too early and break down, it would probably mean another six to eight weeks out."
Bunyan was injured in the Premier Trophy victory over Sheffield at Loomer Road on 10 April.
Former world champion Gary Havelock and Birmingham's Jason Lyons have been among the riders that have raced for Stoke as a guest in Bunyan's absence, with Lyons scoring 10 points in the 52-37 victory over Somerset in the Premier League on Saturday.
"Although we have had very good guests to cover me, and the team is winning, it is frustrating for me," continued Bunyan.
"I want to be out the winning races for the club and continue to move the club forward."
Workington visit Loomer Road on Saturday, with the return leg taking place 24 hours later.