Nottinghamshire batsman Michael Lumb is likely to miss six T20 Blast and three Country Championship matches with an arm injury.
The 34-year-old has been forced to rest for four weeks after injuring himself during his 68-run knock in Notts' six-wicket win over Middlesex on Tuesday.
Phil Jaques comes in as cover for the Outlaws against Leicestershire on Thursday and Derbyshire on Friday.
Steven Mullaney is expected to come into the County Championship side.
England one-day and T20 international Lumb's half-century against Middlesex was his first in 13 innings this season.
"Michael needs a period of rest, which is a blow at this stage of the season given his record in all formats," Notts director of cricket Mick Newell told the club website.
"It's very important that we allow him time to recover and get him back into the side, knowing that Phil Jaques will only be around for three more weeks."