Bell, 3-6, had a procedure to repair a ligament tear after being struck on the foot during practice with Islamabad United in the Pakistan Super League.
He could be out of action for three months.
“Ian will instantly begin his rehab programme,” first-team trainer Jim Troughton said.
“There are always unknowns together with surgery, however, Ian has ever kept his fitness at the top level throughout his career”
Bell, that was forced to miss the Bears preseason excursion of this United Arab Emirates, hit 1027 conducts – including five centuries – in an average of 54.05 since Warwickshire won promotion to Division One at 2018 by raising the Division Two title.