King was ruled out of Saturday's 3-0 home defeat to Doncaster, North End's heaviest defeat of the season, which extends their winless run to eight npower League One games since beating Westley's former club Stevenage in November.
The versatile 27-year-old joined defenders Keith Keane (knee) and Scott Laird (broken leg) and midfielders Lee Holmes (groin) and Nicky Wroe (knee) on the sidelines.
"We have those two (Keane and Laird), Nicky Wroe, Lee Holmes and Jack King went down overnight," Lilywhites boss Westley told his club's official website after the Rovers reverse.
"With those five lads missing we were dependant on two or three young players."
Stuart Beavon is expected to continue in attack after shaking off a hip problem to start at the weekend.