A Season-Ending Patellar Tendon Tear: What the Injury Actually Involves

San Francisco 49ers starting defensive tackle Alfred Collins tore his patellar tendon during practice in Melbourne, Australia, just days before the team's 2026 season opener. Head coach Kyle Shanahan confirmed the injury will keep him out for the entire season.¹ We have no involvement in his care and no independent knowledge of his imaging or prognosis — but the injury is a useful hook for explaining what a patellar tendon rupture is, since it's a different (and in some ways more serious) injury than the ACL tears that tend to dominate sports injury headlines.

A Rope, Not a Ligament

The patellar tendon isn't part of the ACL/MCL ligament group that stabilizes the knee joint itself. It's the thick tendon connecting the kneecap to the shinbone, forming the final link in the knee's extensor mechanism — the chain of muscle and tendon that lets you straighten your leg and push off the ground. A complete tear there doesn't just destabilize the knee; it can leave someone physically unable to extend the knee against gravity at all until it's repaired.²

Why It's Rarer Than an ACL Tear — and Always Surgical

Patellar tendon ruptures make up only a small fraction of knee extensor mechanism injuries overall and tend to occur in younger athletic men, often with some pre-existing tendinopathy that weakened the tissue before the acute tear.³ Unlike many tendon and ligament injuries that can sometimes be managed non-operatively, a complete patellar tendon rupture essentially always requires surgical repair to restore the ability to straighten the knee, using techniques such as transosseous tunnels or suture anchors to reattach the tendon to the kneecap.³

What Recovery Looks Like

Systematic reviews of surgical repair report generally favorable outcomes, with low complication and re-tear rates when the repair is done acutely rather than after a delay.⁴ That said, recovery is a long process: published series following athletes back to sport after repair report a mean of around 9 months before return to running and considerably longer — well over a year, in some series — before athletes return to their pre-injury level of competition.⁴ That timeline is a meaningful part of why this type of injury is often season-ending rather than a multi-week absence.

The Takeaway

Not every serious knee injury in the news is an ACL tear. A patellar tendon rupture involves a different structure altogether, requires surgery in essentially all complete cases, and carries a longer road back to full sport than many ligament injuries. The distinction matters for understanding why some athletes described as having a "season-ending knee injury" are back in a matter of months, while others are looking at the better part of a year or more.