The visitors won the toss and decided to bat against a Warwickshire side which included New Zealand international Chris Martin as well as Chris Woakes who had recovered from injury.
Salisbury took the wickets of O'Brien (48), Peters (50), Sales (4) and White (73) to give himself first day figures of 4-79 from 22 overs.
Neil Carter took the wicket of Wessels for 61 as Northants closed on 292-5 after 72.1 overs.
Meanwhile, Warwickshire have announced that they are releasing Coventrian Luke Parker. Lee Daggett has also been released and is currently in talks with Leicestershire and Michael Powell has also been told that he can leave.
In the Fourth Test at The Oval, Kevin Pietersen got his England captaincy off to a good start when his former South African team were bowled out for 192.
Ian Bell took two catches as did Tim Ambrose and the Coventrian was 22 not out as England closed on 49-1