Doctors Explain Why Blood Clots Are More Common in Athletes Like Bucks' Damian Lillard

The nine-time All-Star is out indefinitely with the ailment.

Mar 24, 2025; Phoenix, Arizona, USA: Milwaukee Bucks guard Damian Lillard before the game against the Phoenix Suns at Footprint Center. Mandatory Credit: Mark J. Rebilas-Imagn Images / Mark J. Rebilas-Imagn Images

Nine-time All-Star Milwaukee Bucks point guard Damian Lillard has been on the shelf since a 104-93 defeat to the Golden State Warriors on March 18.

He is grappling with a deep vein thrombosis (a.k.a. a blood clot) in his right calf.

Damian Lillard has been diagnosed with a deep vein thrombosis (blood clot) in his right calf and is out indefinitely

Lillard is on blood-thinning medication, which has stabilized the blood clot, and will continue with regular testing pic.twitter.com/0wlYbZl8hD

— Bleacher Report (@BleacherReport) March 26, 2025

If Lillard cannot return to the 41-34 Bucks in time for the playoffs, that's essentially game over for Milwaukee's title aspirations.

So, ahead of a critical postseason, how worried should fans be about Lillard's short-term — and long-term — health?

Jared Weiss of The Athletic recently consulted with multiple doctors about the ins and outs of deep vein thrombosis — an issue that forced the San Antonio Spurs to sit All-Star center Victor Wembanyama for the rest of the year just a few months ago and that compelled former 11-time All-Star Miami Heat center/power forward Chris Bosh to retire.

There is an acronym going around the NBA world lately that has been raising as many questions as alarms: DVT.

What is Deep Vein Thrombosis?

We spoke with doctors to learn more about the ailment impacting Damian Lillard, Victor Wembanyama and others ⤵️ pic.twitter.com/THQHdWnocS

— The Athletic (@TheAthletic) April 3, 2025

When it comes to the cause, it turns out that a big element of the risk factor comes with the territory of being a professional athlete. A vascular surgeon at Memorial Orange Coast Medical Center in Fountain Valley, California, Dr. Christopher Yi, broke it down for Weiss.

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“It’s not genetics or familial. It just randomly happens in certain people and is more common in people who have repetitive arm movements,” Yi said. “Wembanyama, that’s probably what’s going on with him. In golf, Nelly Korda had that. It’s just sort of random people with repetitive arm movements.”

Lillard, a prolific jump shooter, would fit the profile of someone stuck in the midst of repetitive arm movements. Lillard is currently on blood thinners. Per Weiss, blood thinners make "the body more prone to excessive bleeding from contact and cuts." It's for this reason that Lillard is not permitted to suit up while still taking the anticoagulants.

How long will it take Lillard to return to on-court activities?

“The recovery is unpredictable and it’s all based on how long it takes for the blood clot to dissolve,” said cardiologist Dr. Cheng-Han Chen, who serves as the medical director of the Structural Heart Program at Laguna Hills, California's Saddleback Medical Center. “Depending on the person, the time it takes for the blood clot to resolve could be anywhere from three months to a year."

For now, the Bucks are attempting to determine the cause behind the blood clot, as Yi explained.

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“Trying to figure out what caused it and the length of treatment,” Yi said of Milwaukee's approach. “Whether he needs to be on blood thinners for long term or short term. I’m not sure about his recovery and prognosis, but I’m not sure players in the NBA can continue competing at a high level while being on blood thinners. Definitely not football. Golf is probably OK, but being on blood thinners in a contact sport can be risky. Any injuries or heavy contact can cause internal bleeding.”

Lillard is hoping to return in time for the postseason. He sat out two of the Bucks' six games in their first-round upset loss to the Indiana Pacers last season with an injury, while Giannis Antetokounmpo missed all of them. At 34, time is rapidly running out for the future Hall of Famer to be an impact player on a title team.

Per Yi, the plan with Lillard's issue is to hope to avoid the clot spreading.

“If you get blood clots in the legs and they go to the lung, a PE, the recovery is much different,” Yi said. “You need to be on long-term blood thinners. You may have long-standing effects on leg swelling and lung function. That’s when you sometimes see athletes have to retire.”

As a lower extremity ailment, there is also an ominous risk that the clot can move somewhere even more concerning.

“The reason why DVTs are concerning — the lower extremity more so than the upper extremity — is their predilection to migrate to the heart,” chairman of the department of cardiovascular thoracic surgery at the West Virginia University Heart and Vascular Institute Dr. Vinay Badhwar said.

In 58 healthy games this season, the 6-foot-2 Weber State product is averaging 24.9 points on .448/.376/.921 shooting splits, 7.1 assists and 4.7 rebounds a night.

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