The Blues said Berglund was injured during an offseason conditioning program in Sweden and flew to St. Louis for Tuesday’s procedure. The team called it a successful surgery.
The 29-year-old Berglund scored a career-high 23 goals and finished with 34 points in 2016-17, adding four assists in 11 playoff games.
Berglund has spent his entire nine-year NHL career with the Blues, scoring 296 points in 637 regular-season games.
The Blues also re-signed 30-year-old defenseman Chris Butler to a two-year, two-way contract. The veteran has 13 goals, 71 assists and 185 penalty minutes in parts of 388 NHL regular-season games.