Jamie McCart and Donovan Pines are getting closer to contention for first team starts but may not return to the Barnsley 11 for Saturday’s game against Leyton Orient.
Pines, the American international centre-back, signed in January but has not played for more than four months.
He was an unused substitute for the 1-1 draw at Bolton Wanderers on Saturday then played 62 minutes of a friendly against Notts County on Tuesday.
Collins said: “It wouldn’t be optimal to start Donovan. Based on his level of fitness, if we needed to, we could.
“He did really well for the under 21s but it was his first game in four months and it’s totally different to playing League One game.
“I would be more than happy if we decided Donovan was available.”
McCart has missed the last five games with a calf problem. Collins said: “Jamie is in contention for Saturday which is good. He is progressing very well.”
Barnsley’s back three at Bolton on Saturday was Jordan Williams, Mael de Gevigney and debutant Josh Earl.
Collins said: “We have good options. Where Jamie and Donovan are at makes the decision slightly easier for now.
“Jamie needs training under his belt but he has been excellent
“We signed Donovan for a reason. But the three lads who played on Saturday did really well.”
Barnsley won the friendly 2-1 with goals by Aiden Marsh and Aaron Atkinson.
Barnsley under 21s are due to visit Sheffield United on Tuesday.
Barnsley under 18s visit Fleetwood Town on Saturday.