This is the team I would pick in a 4-2-3-1 formation.
I’m assuming Jack Taylor and Siriki Dembele are not fit enough to start. Both would be shoo-ins for selection if available.
1. DAI CORNELL
If the point of making seven changes to the team that faced Plymouth in the Carabao Cup on Tuesday was to see who's in form than goalkeeper Cornell must be selected tomorrow. He let four goals in, but made multiple fine saves to keep Posh from an even bigger drubbing. I remain unsure about Christy Pym. On seeing Luton's first goal back last Saturday I wondered if he could have saved what was a pretty tame header. His short passing out from the back is unconvincing.
2. NATHAN THOMPSON
It clearly won't be quite so easy for Thompson to impress at right-back this season. He will be much more comfortable in the middle of a back three, but Derby are likely to play one up top tomorrow so three centre-backs would be a waste for a team looking to win at home. Thompson is the only natural right-back in the squad even though versatile Joe Tomlinson was tried there on Tuesday night. I'm backing his cleverness and competitive nature to overcome a shortage of pace.
3. DAN BUTLER
Posh obviously rate newcomer Tomlinson highly and it would be interesting to see how he went in his best position of left-back. For now Butler's greater experience in what is likely to be a tense game in front of the live TV cameras is preferred. He will need to sharpen up on his performance at Luton to fend off Tomlinson for much longer.
4. JOSH KNIGHT
We bought Knight to play at centre-back and he performed heroically in that position in the Championship for Wycombe last season so I'm throwing in him ahead of Frankie Kent who has struggled in both outings so far this season. Knight's presence won't help the tactic of passing the ball around the back, but maybe getting the ball to the more gifted forward players much more quickly would be a good thing. If Posh are going back to basics tomorrow let's have the defenders concentrating on their defending rather than pretending they're Bobby Moore and Alan Hansen.