The Irish striker, who has scored five goals since signing in October, has shaken off the knock which has kept him out of the last two games.
Connolly will partner 15-goal top scorer Rickie Lambert in attack, with Senegalese forward Papa Waigo set to drop out of the starting line-up.
Saints are still without goalkeeper Kelvin Davis with a groin injury so Bartosz Bialkowski continues to deputise.
Veteran defender Chris Perry has earned a recall in the last two games so on-loan Neal Trotman looks likely to have to settle for a place on the bench again.
Out-of-favour striker Marek Saganowski is still unavailable with a knee injury.