Glentoran will be under major pressure going into the Boxing Day Carnegie Irish Premier League clash against Linfield at the Oval (1720 GMT).
Mouncey (left) is unlikely to face Colin Nixon and Co. at the Oval
The Glens are five points behind the Blues and another defeat would leave the east Belfast club with a lot of catching up to do in the title race.
Linfield are likely to be without Tim Mouncey (flu).
Thomas Stewart should be available after recovering from injury as should fit-again Paul McAreavey.
Midfielder McAreavey has been out of action recently because of a virus but he was on the bench for Saturday's home win over Glenavon and he could see some action in Wednesday's Big Two clash.
Stewart came on as a first-half substitute against the Mourneview Park outfit.
Oran Kearney will have hopes of earning a start at the Oval after coming on as a substitute for the second weekend in a row on Saturday.
Kearney recently returned to fitness after being out of action for almost a year because of a cruciate ligament injury.
Conor Downey could also see some action at the Oval after playing for Linfield Swifts in a number of recent games.
Former Cliftonville star Downey has also been out of action for some time because of injury.
One of the big talking points for Wednesday's game will be whether Glenn Ferguson is going to bring up his career goals tally to 500.
Ferguson reached the 499-mark by scoring in the 3-2 victory over Glenavon.