Easter begins a two-match ban after picking up his 10th booking of the season at Stockport on Saturday to go with his 16th goal of the campaign.
Sam Baldock will replace him alongside Aaron Wilbraham but manager Paul Ince has selection problems in defence as his side look to overturn a 1-0 deficit from the first leg at St Mary's.
David McCracken played with a broken nose in the 3-1 win at Stockport but had to come off at half-time with a calf strain and he will be missing while fellow centre-halves Sean O'Hanlon (knee), Mat Doumbe (groin) and Darren Powell (knee) are also out.
Wingers Luke Chadwick (knock) and Andros Townsend (cup-tied) are also missing to leave Ince with a headache.
Ince won the trophy in his first spell with the Dons in 2008 and is keen to regain the trophy.