Starting goalkeeper Liam Roberts will return after being suspended for the first leg.
The Cobblers are still unsure about the fitness of forward duo Louis Appere and Josh Eppiah. Appere limped off in the 66th minute of the first leg while Eppiah was only fit enough to play the final 35 minutes and a late decision may be made on the pair.
Doubts still remain over the fitness of defender Aaron McGowan.
Fellow midfielders Jordan Bowery and George Maris will be assessed prior to kick-off.
Left-back Stephen McLaughlin, the Players Player of the Season is also scheduled to be assessed, but he says he is "ready to go".
Northampton Town: Maxted; Horsfall, Guthrie, Mills; Kanu, Sowerby, McWilliams, Koiki; Pinnock; Appéré, Hoskins
Mansfield Town: Bishop; McLaughlin, Hawkins, O'Toole, Perch; Longstaff, Maris, Murphy; Quinn; Oates, Bowery
Ones to watch
Sam Hoskins (Northampton Town)
All eyes will be focused on the Cobblers' top scorer after he wasn't much involved in the first leg. How Northampton establish him early on will be critical to the outcome of the tie.
Stephen McLaughlin (Mansfield Town)
The Stags left-back was voted as the Players Player of the Year and is a towering presence in defense. His ability to contain Northampton on the left as well as get involved in the Mansfield attack when he can is another key component to this second leg.
Mansfield established control of the first leg when Bowery's exquisite found Oates and he managed to keep himself onside to fire through the legs of goalkeeper Jon Maxted.
The lead was doubled shortly after the half-hour mark when Newcastle loanee Matty Longstaff switched the ball from the right to Jamie Murphy on the left, whose cross hit Maxted and dropped for Bowery, who had a simple finish.
Northampton cut into the deficit as Louis Appere charged down the left, steadied himself and worked the ball to Koiki, whose deflected shot found its way into the net to set up an intriguing second leg.
The match will be shown live on Sky Sports Football and Sky Sports Main Event with coverage beginning at 7:30pm. Kick-off is set for 7:45pm.