Cartwright made one appearance for the Posh due to a reoccurring injury problem, playing the full game in a 2-1 defeat against Stevenage in Group B of the EFL Trophy back in August.
The England Under-20 international was also an unused substitute in Peterborough’s 2-1 League One defeat against Derby County three days prior to his Posh debut.
Robson featured six times for Crawley, saving a penalty on his debut in an 8-7 shootout win over Portsmouth in the EFL Trophy.
Making a further two appearances in the competition, the Wales Under-21 international featured three times in League Two in fixtures against Newport County, Mansfield Town and Colchester United.
