Pompey travel to Plymouth tomorrow and could move up to fifth in League One if results go their way.
Kenny Jackett's troops are currently seventh on 62 points but could leapfrog the fifth-placed Pilgrims (63) with a victory at Home Park.
Meanwhile, Charlton (62) - who occupy the final play-off berth on goal difference - host top-six chasing Scunthorpe United at the Valley.
The Addicks are looking to bounce back after suffering a 1-0 defeat at AFC Wimbledon on Tuesday.
The Blues could, however, drop to ninth if they fall to a loss at Plymouth.
The Iron (61) will be looking to reignite their play-off charge at Charlton under caretaker boss Nick Daws.
Scunthorpe have won just one of their past 15 fixtures.
Eighth-placed Peterborough United (61) host relegation-battling Rochdale at London Road.