Trotter boss Gary Megson is ready to draft in his summer additions and that means a new-look back four, with Knight set to partner Gary Cahill in central defence.
Ricketts is expected to replace Gretar Steinsson at right-back after impressing in pre-season while Jlloyd Samuel could also make way at left-back for Robinson.
Davis will play in central midfield but it remains to be seen whether Gary Megson will play a 4-5-1 formation or go 4-4-2, with Kevin Davies and Johan Elmander leading the attack.
Hibernian head coach Neil Lennon claimed referee John Beaton failed to protect his players from 'disgraceful' challenges during a 1-1 draw with St Johnstone.
St Johnstone manager Tommy Wright has accused Neil McCann of deflection tactics as he denied reporting the Dundee boss to the Scottish Football Association.