The Sweden international missed Friday night’s 4-0 FA Cup fifth-round defeat at Chelsea after reaching 10 bookings for the season in the 2-0 league win at Nottingham Forest the previous weekend.
Striker Hernandez played 55 minutes for the club’s under-23s on Monday afternoon after six months out with a ruptured Achilles tendon, although he is still working his way back to match fitness.
On-loan Chelsea trio Michael Hector, Ola Aina and Fikayo Tomori are available after being ineligible to face their parent club, but Markus Henriksen (ankle), Ondrej Mazuch (hamstring), Moses Odubajo and James Weir (both knee) are still out.
Preston are reportedly weighing up whether or not to make a fourth offer for Peterborough United left-back Andrew Hughes.
James Maddison has completed his move from Norwich City to Leicester City for an undisclosed fee.
West Ham United are reportedly weighing up a summer bid for Amiens forward Moussa Konate.