Winger Jacobs missed the 1-1 draw at Burton in midweek through illness while Johnson missed out with a thigh strain.
Johnson said: "Michael and John should both be close for Saturday. No disrespect to the rest of the squad but at the moment they are probably our two most consistent performers and to have them back in the team would give us a massive lift for Saturday."
Johnson's absence led to a reshuffle in the back four at Burton, with Dean Beckwith filling in at right-back and Marcus Hall moving to centre-half.
Captain Andy Holt remains a doubt with his knee problem while midfielder Ryan Gilligan has had surgery on a long-standing ankle problem and is sidelined for the rest of the season.
Striker Billy McKay is out for another month after dislocating his elbow but Leon McKenzie is back in the squad after a knee injury.
Source: PA
Source: PA