Regan was sent off in the Pirates` 3-0 defeat to Leyton Orient last weekend and serves the first game of his three-match suspension, while fellow loanee defender James Tunnicliffe is unavailable to play against his parent club.
Trollope will have to shuffle his backline in the pair's absence, with Byron Anthony, Jeff Hughes and Gary Sawyer all likely to adopt roles in the Rovers defence.
Will Hoskins is still sidelined with an ankle injury and needs at least another three weeks to regain his fitness while Charlie Reece is also unavailable due to a back injury.
On-loan striker John Akinde is a major doubt for the trip with an ankle problem.
Source: PA
Source: PA