The Cleveland Guardians have called up top pitching prospect Gavin Williams to make his major league debut Wednesday against the Oakland Athletics, while starting pitcher Triston McKenzie will be shut down for up to six weeks — and possibly longer — with an elbow sprain that may yet require surgery.

Williams, 23, has risen quickly through the Guardians organization, and the club feels it’s time to see how his electric fastball plays against the game’s best players. A first-round draft pick in 2021, he is ranked No. 36 on ESPN insider Kiley McDaniel’s updated list of top 50 prospects.

The Guardians, who are two games behind first-place Minnesota in the AL Central, announced Williams’ start before opening a three-game series against the A’s.

Williams has gone 4-2 with a 2.39 ERA this season at Double-A Akron (three starts) and Triple-A Columbus (nine starts). He has 81 strikeouts in 60 innings. Last season, Williams struck out 149 in 115 innings.

McKenzie, 25, was placed on the 15-day injured list over the weekend with a strained ulnar collateral ligament. Guardians team physician Dr. Mark Schickendantz evaluated McKenzie at the Cleveland Clinic and advised he not throw for an extended period.

McKenzie, who missed the season’s first two months with a shoulder strain, will seek a second opinion with the team’s blessing. While he has long been viewed as a potential ace for Cleveland, McKenzie has also been slowed by injuries throughout his career.

McKenzie’s injury is the latest for the defending AL Central champions, who are also without starter Cal Quantrill because of a shoulder strain.