The Offaly U-20 star is said to have picked up a muscular injury.
Tullamore will have to make do without one of their star youngsters if they're to claim the Offaly Senior Football Championship.
Manager Niall Stack estimates the All-Ireland winner could be out for at least a month after 'his body gave up on him'.
Egan had a hectic schedule in recent months, competing in two minor semi-finals at club level just days after climbing the steps of Croke Park.
It appears as if that effort as well as his status as a dual player has taken a toll on his fitness.
Speaking after defeating Ferbane, Stack said:
'It is taking a toll on the body. You can see it in other clubs too. We need to mind that U-20 squad as best we can when the season is over and give them a rest.
I'm not throwing blame at anyone regarding fixtures, it is what it is but we just need to mind that group.'
Stack went on to namecheck Cathal Flynn, Jack Bryant and Cormac Delaney as players from other clubs who have a similarly active schedule.
Addressing Egan's injury directly, The Tullamore boss told Midlands103:
'It's unlikely Cormac will play in the next two weeks and as they say recovery is half your training.
It's good to see good dual clubs up at senior level like Ferbane, Belmont, Durrow, Ballinamere and ourselves.
I suppose Rhode have a natural advantage in that way in terms of being able to concentrate on one sport and they have had that advantage over the years.'
His comments came in the aftermath of watching his young team advance to the championship decider through a brace from Luke Egan and further strikes from Shane Dooley and Luke Plunkett.
It's Tullamore's second county final in succession and many shrewd commentators can see them once again becoming a mainstay at the business end of the campaign.
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