Winger Cotterill, 24, completed his move to Oakwell until the end of the season this week, but is short of match fitness following his release from Swansea last month.
Another recent signing, former Orient skipper Stephen Dawson (ankle), is hoping to be in contention for his first appearance and could also be included on the bench.
Defender Bobby Hassell sustained a knee injury in training this week and will be sidelined for a fortnight, but winger Jim O'Brien is pushing for his first start since Boxing Day.
He stepped off the bench in the midweek defeat at Burnley after recovering from a niggling groin injury.
Barnsley slipped to back-to-back away defeats last week and are 12 points adrift of the play-offs.