Munster spoke to the Melbourne Storm's club website during the media day ahead of Week 1 of the NRL finals, confirming there is no guarantee his stitches would hold up.
The news comes after a cut he sustained in the Round 24 shock loss to the Parramatta Eels became infected. It caused him to be rested from the Round 25 victory over the Cronulla Sharks as the men in purple locked up the minor premiership.
"It's a bit of a healing process. I can still play on Friday, but they can't guarantee the stitches will hold up," Munster told the club website.
"It's a 50-50 call between me and the coaching staff.
"We could win, open it up, have the week off and who knows, I could be back to square one. But if I play, open it up and we lose and then I've got to try back up the following week so it's a tough situation we are in."
The Storm will have a qualifying final this weekend against the Manly Sea Eagles, meaning the minor premiers do have a second chance should they fail to pick up the win.
Munster is confident the club have the players to get the job done this weekend with or without him.
"I'm sure we have enough good quality players in our team. We have some solid players in the halves and I'm sure they will fill the void immensely," Munster said.
The Storm's clash with Manly will be held at the Sunshine Coast Stadium on Friday evening with kick-off slated for 7:50pm (AEST).