The defender pulled out of the Northern Ireland squad to face Malta in a World Cup qualifier this week with a hamstring problem but could train on Friday.
Tim Clancy is also nursing a hamstring injury after missing the Scottish Cup win over Aberdeen on Sunday.
Fenlon said: "We are still waiting on Tim Clancy and Ryan McGivern.
"Both of them did light work this morning and we're hoping Ryan will come into the group tomorrow and Tim hopefully Saturday or Sunday.
"Ryan has a very good chance of making it and Tim is a bit of a 50-50 at the moment."
The two-day wait for the game could also benefit midfielder Jorge Carlos, who was a late sub as Honduras beat the USA last night in a World Cup tie.
"It gives him a little bit more breathing space," Fenlon said.
"If the game was Saturday or Sunday the travelling might not have done him any good so hopefully we will get him back all right and he is fit to play."
Fenlon also confirmed striker Leigh Griffiths would be in the squad.
The 22-year-old was charged under the Communications Act on Monday following a police investigation into an alleged racist tweet.