Leicestershire captain Ramnaresh Sarwan has been ruled out for the remainder of the season due to a back injury.
The 34-year-old West Indies batsman has played just five Championship games for the Foxes this season and, following medical advice from the club, it has been decided he is to return home to Guyana.
"I am naturally very disappointed to have had my season cut short at Grace Road this season," he said.
"It has been a frustrating time not being out in the middle with the lads and I want to wish all the players and the coaching staff the best of luck for the rest of the season.
"I am confident that this time to recuperate and undergo my rehab will give me the best possible chance of representing the West Indies in next year's ODI World Cup and I have my eyes set on returning to county cricket in 2015."
Scott Styris will replace Sarwan in the Royal London One-Day Cup after agreeing to extend his stay with Leicestershire.
The New Zealand veteran initially joined the county for this season's Natwest T20 Blast but has now agreed to stick around for the 50-over competition as well.
Styris will also serve as one-day captain while Josh Cobb recovers from a fractured thumb.