Barnet are anxiously awaiting news on the ankle injury suffered by defender Daniel Leach during the 4-1 defeat by Rotherham on Saturday.
The 24-year-old Australian limped off during the first half - when the score was 0-0 - and left Underhill on crutches.
"Up to that point there was only one team going to win it," said manager Mark Stimson.
The Bees are already without centre-half Darren Dennehy until the new year with a foot injury.
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