MK Dons have succeeded in their appeal to overturn Stephen Gleeson's sending-off in the first-leg victory over Peterborough.
Gleeson received a straight red card from referee Jon Moss in the 80th minute of the 3-2 win for denying an obvious goalscoring opportunity.
The club submitted an appeal to the Football Association on Monday citing wrongful dismissal and the decision was made to rescind the card.
As a result, the midfielder is available to play in Thursday's second leg at London Road.
Dons manager Karl Robinson said: "It's great news. We all felt the FA would make the correct decision and I am glad that it's gone through the right avenues.
"Stephen has been in fantastic form all season and he deserves his chance to help get this club into the final."