The Northern Irishman was initially ruled out for six weeks with a shoulder injury sustained in the goalless draw at Kilmarnock a month ago, with 41-year-old goalkeeping coach Steve Banks deputising in the last three games.
However, Saints boss Wright revealed Mannus is back in full training although he will not take a risk on his fellow Northern Irishman.
Before training at Stirling University this morning, Wright said: "Alan Mannus has trained all week and we will see how he does today. I will make a decision tomorrow on who starts.
"It is not a gamble I need to take. Whoever I decide to play, it will be the right decision for the team, not the individual.
"We won't risk him and we have no need to risk him because Steven Banks has been excellent but that will be a decision made tomorrow."
Wright revealed more good news on the injury front in the shape of midfielder David Robertson, who broke a leg against Hibs at McDiarmid Park last November.
He said: "Everyone is really pleased that David Robertson got through 45 minutes in an under-20 game (in midweek) so everyone in and around the senior squad is fully fit."