The Incident(s)
No player on this site lost more time to injury than Klay Thompson — and no player's story better illustrates how one serious tear can compound into two.
The first came in Game 6 of the 2019 NBA Finals, June 13, 2019, as the Golden State Warriors tried to force a Game 7 against the Toronto Raptors. Thompson tore the ACL in his left knee on a non-contact landing, ending his night and, though no one knew it yet, his entire 2019–20 season.
He underwent ACL reconstruction on July 2, 2019, and began what was expected to be a standard, if lengthy, road back. Seventeen months later — on November 18, 2020, during an offseason pickup workout in Los Angeles — Thompson ruptured his right Achilles tendon. It was a second consecutive season wiped out before it started, and one of the cruelest injury sequences of the modern NBA era.
Two Different Injuries, Two Different Mechanisms
Thompson's two injuries, though both non-contact, are mechanically distinct. The ACL — a ligament stabilizing rotational movement in the knee — typically fails during a plant, cut, or awkward landing, when the knee absorbs more rotational force than the ligament can withstand.
The Achilles tendon, by contrast, connects the calf muscles to the heel and drives plantarflexion — pushing the foot downward, the motion behind every sprint and jump. It ruptures under a different kind of load: forceful, often sudden loading of a tendon that has poor blood supply and, as with Durant and Rodgers elsewhere on this site, becomes more vulnerable with age and prior injury history.
There is a documented, if not fully understood, association between a major lower-body injury and elevated risk to other structures in the kinetic chain during the return process — compensatory movement patterns built up over a long layoff can shift load onto tendons and ligaments that weren't the original injury site. Thompson's case, two significant injuries in overlapping recovery windows, is frequently cited as an example of that pattern, though it cannot be said with certainty that the ACL recovery caused the Achilles tear.
The Surgical Decisions
Both injuries required surgery. The ACL reconstruction came first, on July 2, 2019. The Achilles repair followed on November 25, 2020, performed by Dr. Richard Ferkel in Los Angeles, and was described at the time as successful, with an expected recovery sidelining Thompson for the entire 2020–21 season.
Rehabilitation: Phase by Phase (Achilles Repair)
Because Thompson's Achilles rupture was the injury that most directly echoes the other tendon cases on this site, the phases below focus on that recovery — effectively his second full lower-body rehabilitation in under two years.
Phase 1 · Weeks 0–6
Protection & Rest
Non-weight-bearing progressing to partial weight-bearing in a protective boot. With a surgically reconstructed knee on the same leg from the prior year, clinicians paid particular attention to whole-limb strength and alignment, not just the Achilles repair in isolation.
Phase 2 · Weeks 6–12
Early Mobilization
Boot weaning, active range-of-motion work, and pool-based rehabilitation. Given the compressed injury history, rehab staff also emphasized hip and core stability work to reduce compensatory strain elsewhere in the leg.
Phase 3 · Months 3–6
Strength Restoration
Single-leg calf raise progressions and controlled plyometric loading, closely monitored against the previously reconstructed ACL to ensure neither structure was compensating unfairly for the other.
Phase 4 · Months 6–12
Return to Sport
Multi-directional movement, defensive slides, and shooting-specific footwork — the jump-stop and elevation mechanics central to Thompson's game as a shooter. Confidence in the leg, after two serious injuries in as many years, was as much a rehabilitation target as strength itself.
Phase 5 · Months 12–18+
Performance Restoration
Full practice participation and eventually game readiness. After more than two years without competitive basketball, conditioning and game rhythm needed as much rebuilding as the tendon itself.
Return-to-Play Timeline
Thompson's full return to competitive basketball came more than two years after the ACL tear that started the sequence — and roughly eleven months after the Achilles surgery that followed it.
Thompson returned for the Warriors' 2021–22 season opener in October 2021 — his first competitive game in 941 days. That season, Golden State won the NBA Championship, with Thompson a key contributor in the playoff run. It stands as one of the more complete comeback stories in the league, precisely because it required rebuilding from two different injuries rather than one.
What the Research Says
Thompson's case sits at the intersection of two well-studied injury literatures:
- Sequential lower-body injuries in elite athletes are associated with longer overall time away from competition than either injury would predict in isolation, partly due to conditioning loss and partly due to more conservative, staged rehabilitation.
- NBA-specific Achilles outcomes (see the Kevin Durant analysis on this site) show meaningful performance decline in the first season back is common; Thompson's case is notable for how quickly he returned to a high level once he did return, contributing to a championship run in his first season back.
The Verdict
Klay Thompson's two-injury sequence — a torn ACL followed, seventeen months later, by a ruptured Achilles — represents one of the longest single-player layoffs in recent NBA history: two and a half years between his last game before the ACL tear and his return in October 2021.
Both injuries individually carried standard, well-understood recovery timelines. Together, they turned what might have been a single lost season into a defining test of patience — for Thompson, and for a franchise that waited for him. The eventual payoff, a championship in his first season back, is a reminder that a long layoff is not the same as a diminished return.
Sources
- "Report: Klay Thompson Undergoes Successful Knee Surgery to Repair ACL Injury." Bleacher Report. July 2019. bleacherreport.com
- "Klay Thompson Undergoes Successful Surgery to Repair Torn Achilles." NBA.com. November 2020. nba.com
- "Klay Thompson injury latest: Warriors star ruled out for 2020–21 NBA season with Achilles tear." CBS Sports. November 2020. cbssports.com
- "Klay Thompson's grueling road back from two serious injuries." Fox Sports. 2021. foxsports.com
- "Case report: Klay Thompson's injury journey." Sports Injury Bulletin. sportsinjurybulletin.com
Disclaimer: This analysis is based on publicly available information and published medical literature. It is not a diagnosis of the athlete's condition, and the actual injury, severity, rehabilitation plan, and return-to-play timeline may differ.