Tomlin will be suspended when the only team below Posh in the npower Championship table visit London Road on New Year's Day.
The 23-year-old was shown a straight red card after just 12 minutes on Saturday for elbowing Bristol City defender Greg Cunningham as Peterborough's three-game winning run crashed to a halt with a 4-2 defeat at Ashton gate.
Tomlin will begin a three-match ban with Danny Swanson the man most likely to replace him in the starting line up against the Tykes, who sacked manager Keith Hill at the weekend after losing 3-1 at home to Blackburn.
The only change to the Posh side against Bristol City saw Grant McCann replace George Thorne in midfield after the teenager was recalled from his loan spell by parent club West Brom on Friday.
- Sports & Recreation
- Bristol City
- Greg Cunningham