The duo were missing on Tuesday as the Bluebirds dropped two points at home to Barnsley but boss Malky Mackay is hopeful they will be passed fit.
Striker Campbell suffered a shin injury during the Easter Monday win over Blackburn while defender Connolly suffered a groin strain last weekend against Watford.
Centre-half Leon Barnett has extended his loan deal from Norwich until the end of the season.
Cardiff are six points clear at the top of the table and need seven points from their final five games to make sure of promotion to the Premier League.
Billy Davies, meanwhile, expects to have an unchanged squad to choose from for Nottingham Forest's trip to Championship leaders Cardiff.
It means the Reds boss has plenty of options at his disposal should he wish to make any changes to his starting line-up in the Welsh capital.
Lewis McGugan staked his claim for a recall by coming off the bench to score a late penalty and rescue a draw for Forest for the second game running against Blackpool last weekend.
Fellow midfielder Guy Moussi, defenders Sam Hutchinson and Danny Collins and strikers Dexter Blackstock and Billy Sharp were Davies' other substitutes against the Tangerines.
Stephen McLaughlin (ankle) remains the only injury absentee. The winger is still waiting for his first taste of first-team action since joining the Reds from Derry City in January.