Claude Davis is ruled out of Crawley's game against Colchester United at Broadfield Stadium today.
The Jamaica international suffered an injury in the 3-0 defeat to Bournemouth on Saturday and joins fellow centre back Kyle McFadzean.
That means Joe Walsh comes into the team alongside Mark Connolly in an inexperienced central defensive partnership.
Top scorer Billy Clarke also comes back into the starting line-up at the expense of Shaun Cooper as boss Richie Barker reverts to a 4-4-2 formation from the 4-5-1 he used at Dean Court.
The other change sees Hope Akpan return from a one-game ban with Dannie Bulman dropping to the bench.
There is no place for new signing Lateef Eldorf-Alliyu in the matchday squad following his arrival from Bury this morning on a six-month contract.
Young forward Jonte Smith does keep his place on the bench though with Nathan Byrne also coming back into the squad and John Akinde dropping out of the 18 altogether.
Colchester make four changes to the side which lost 3-1 at home to Brentford on Saturday.
Former Crawley defender Magnus Okounghae comes into the side but another ex-Red Tom Eastman drops out through injury. There is also a recall for star midfielder Anthony Wordsworth with Brian Wilson and Matt Heath also starting.
Colchester feature two new signings - George Porter and Jack Compton - on the bench.
Crawley (4-4-2): P Jones; Hunt, Connolly, Walsh, Sadler; Adams, Akpan, Simpson, M Jones; Clarke, Alexander. Subs: Kuipers, Byrne, Torres, Bulman, Ajose, Cooper, Smith.
Colchester (4-3-3): Cousins; Wilson, Okounghae, Heath, Potts; Wordsworth, Izzet, Bean; Massey, Morrison, Wright. Subs: Compton, Porter, Pentney, Bond, Rose, Sears, Gilbey.