Neither Gladwin (knee) nor Whittingham (calf) have played in 2018 but both have returned to training and are expected to come back into Tony Mowbray’s squad soon.
Craig Conway (hamstring) has been in full training too, with Harry Chapman (hamstring) the only other long-term absentee.
Mowbray, who is hopeful Dominic Samuel (ankle) can overcome his injury, will also have defender Lewis Travis available again after he completed a three-match suspension.
Nick Powell and Nathan Byrne will return to the Wigan fold at Ewood Park.
Neither Powell (hamstring) nor Byrne (calf) were risked in the win over Rochdale last weekend, and Tuesday’s trip to Bristol Rovers was postponed so they have had ample time to recover.
Boss Paul Cook will also get midfielder Samy Morsy back from a two-game suspension that prevented him from featuring against Dale and in the FA Cup win over Manchester City.
Third-placed Latics are currently six points behind table-toppers Rovers but have four games in hand.
Cardiff remain unhappy with Derby's decision to postpone Sunday's Sky Bet Championship game at Pride Park.
Dundee United boss Csaba Laszlo has been left hoping for St Mirren to slip up in the race to seal promotion to the Ladbrokes Premiership.
Crewe will consider starting Chris Dagnall when they host Forest Green on Tuesday.