Rene Howe will miss Torquay's crunch second leg clash at home.
The Gulls' Player of the Year and leading scorer, with 14 goals to his name this season, limped out of Sunday's 2-0 first-leg defeat at Whaddon Road after just 21 minutes nursing a hamstring injury.
Howe, who has also been struggling with groin and knee problems recently, will now miss out at Plainmoor and is battling to make the Wembley final on May 27 should Torquay overturn the two-goal deficit.
Taiwo Atieno replaced the striker on Sunday and is expected to start from the off this time around.
Forward Danny Stevens missed the first leg altogether due to illness but he is likely to be okay.
Meanwhile, Cheltenham will assess Luke Garbutt ahead of the match.
The on-loan Everton full-back missed Sunday's 2-0 first-leg victory at Whaddon Road despite having initially thought he had recovered from a gluteus maximus muscle strain.
But manager Mark Yates insists Garbutt has "got a chance" ahead of the Plainmoor clash.
One or two others are nursing the normal bumps and bruises but are expected to be okay, with goalscorer Ben Burgess fine despite requiring stitches to a head wound which forced him off at the weekend.
Yates must decide whether to keep faith with the 4-4-2 formation which worked so effectively in the first leg or revert to the flexible 4-5-1/4-3-3 system which has served Town so well away from home this season, with Russ Penn competing for a recall.