Jordan Willis returns for the Sky Blues while Jordan Ponticelli makes his first start since November.
Jonson Clarke-Harris and Ryan Haynes also return for Mark Robins' side.
Michael Doyle, Liam Kelly and Tom Bayliss keep their place in the midfield.
Haynes and Willis slot into the defence alongside Grimmer and McDonald.
Ponticelli makes his first Sky Blues start since November's defeat to Mansfield Town. McNulty starts alongside Clarke-Harris in attack, who replaces Biamou.
Lee Burge keeps his place in goal.
Coventry City XI: Burge (GK), Grimmer, Willis, McDonald, Haynes, Bayliss, Kelly, Doyle (C), Ponticelli, McNulty, Clarke-Harris.
Subs: O'Brien (GK), Davies, Stokes, Shipley, Reid, Barrett, Biamou.
Crawley Town XI: Morris (GK), Young, Connelly, Bulllman, Yorwerth, Tajbakhsh, Smith, Payne, Boldewijn, Ahearne-Grant, Verheydt.
Subs: Mersin (GK), Doherty, McNerney, Roberts, Randall, Sanoh, Camara.