Sheehan crashed into Yeovil's Lee Peltier provoking a melee involving just about every outfield player and referee Keith Stroud immediately produced a red card.
Sheehan had no sympathy from his manager Gary McAllister, who said after the game: "He had to go. In this day and age you can't go in with high two-footed tackles like that."
Yeovil boss Russell Slade also had a moan. His night was marred by the fourth-minute goal that won the game. "It wasn't a goal. There was a handball but the referee didn't see it," he said.
Neil Kilkenny crossed from the right to set up that early strike. He picked out Bradley Johnson at the far post. Johnson's shot was parried by Steve Mildenhall but in the scramble that followed the experienced Dougie Freedman got the ball over the line.
Yeovil's football was neat and precise but it was 20 minutes before they had a real attempt at goal, a header from Marcus Stewart flying over.
Six minutes later they had their best opportunity. Everton loanee Aidan Downes got in a perfect cross for Marvin Williams but his six-yard header was superbly saved by Casper Ankergren.
The Leeds keeper made another fantastic save three minutes from time to prevent a dramatic equaliser. Downes was again involved. He got in a terrific shot which looked to be heading for the bottom corner but somehow the keeper managed to turn the ball round the post.
Leeds' best effort in the second half came in the 69th minute from their big central defender Lubomir Michalik. A thunderbolt of a free-kick from 40-yards had Mildenhall flying across his goal to turn the ball for a corner.