Kluber receives a $1 million buyout, and the club has said it is interested in re-signing him to a contract of lesser value.
The Rangers acquired Kluber from the Cleveland Indians last off-season in exchange for reliever Emmanuel Clase, who was eventually suspended 80 games after testing positive for a performance-enhancing substance.
Kluber lasted only one inning in his lone start for the Rangers before a shoulder injury forced him to miss the remainder of the 2020 season. He tossed just 18 pitches in the inning before exiting with shoulder tightness in a 5-2 loss to the Colorado Rockies on July 26.
The 34-year-old Kluber was diagnosed with a small tear in his shoulder muscle the next day.
Kluber's brief appearance for the Rangers was his first start in almost 15 months after his right forearm was broken by a line drive in May 2019. He was nearing a return that season when an oblique injury sidelined him again, ending his tenure with the Indians.
Since making his MLB debut in 2011, Kluber has posted a 98-58 record with a 3.16 ERA and 1,462 strikeouts in 1,342 2/3 innings. He is a three-time All-Star selection.