Lancashire captain Tom Smith will miss the rest of the season as he needs to have surgery on a back injury.
The 29-year-old all-rounder took over the captaincy from Glen Chapple this season but has only been able to play one County Championship match.
Last summer, Smith took more than 50 wickets in the Championship for the first time and hit 773 runs.
"This is a huge blow for Tom and for the club," said cricket director and head coach Ashley Giles.
"As club captain, Tom remains a very important part of the team and our season, and we look forward to him being able to start the journey to play after the operation."