Croft is moving closer to match fitness after re-signing for the club late last month following his long search for a new employer since leaving Oldham in the summer.
Both Croft and Steven Anderson, who dislocated his thumb when Saints last played Thistle, played a full part in Tuesday's under-20s draw with Falkirk.
Manager Tommy Wright said: "Steven Anderson is still on his way back but he is ahead of schedule and it was good for him to get 90 minutes.
"Lee Croft got 90 minutes and I'll look at him in training over the next two days and see if he is ready for the squad."
Easton is a doubt, though, after missing last weekend's 2-0 defeat by Aberdeen with a calf strain.
"We were hoping to get him back this week but our training plans have been disrupted this week with the pitches being waterlogged," Wright said.
"We are off to train on an artificial pitch and I'm not sure he will be able to take a full part in the session, so that will make him a doubt for Saturday."