Peterborough boss Gary Johnson has warned defender Gabriel Zakuani that he should not expect to walk back into the first team.
Zakuani has missed the entire campaign to date as he recovers from a groin operation but came through the full 90 minutes of a reserve game on Tuesday afternoon.
Johnson said: "I don't believe any manager would break up Kelvin Langmead and Ryan Bennett right now. I have been very pleased with the way they are developing as a pair.
"Gaby did well in the reserves, especially as it was a competitive game. It wasn't a match that he could coast through.
"He has proved that he can play at League One level, but he will have to be patient.
"I was impressed with Carl Piergianni as well. Every time I watch him play he does well and it's useful to have four good centre-backs at the club."