San Diego State starting center Nathan Mensah asked out of the Dec. 28 game against Cal Poly early in the second half, complaining of shortness of breath.

He hasn’t played since, and he might not play again this season.

Citing medical privacy laws, SDSU coach Brian Dutcher has declined to discuss specifics of Mensah’s ailment other than to call it an “ongoing respiratory issue.” But numerous sources close to the program confirmed Mensah was initially diagnosed with a pulmonary embolism, a blood clot in the lungs that is treatable but typically takes months, not weeks or days.

The standard treatment for a pulmonary embolism is a minimum of three months and usually precludes any activities involving physical contact. For Mensah, three months would be late March, or the second weekend of the NCAA Tournament.


“I think there’s an outside chance he could make it back to play at some point this season,” Dutcher said after practice Thursday. “When that is, I don’t know. That will be on the advice and recommendation of the medical personnel looking after him.

“First and foremost, we’re going to err on the side of Nathan’s health. When he gets clearance that he’s medically fit to compete again, we’ll look forward to getting him back on the floor.”

Through a team spokesman, Mensah declined to speak about his condition. It is unclear whether it is related to his illness during a Dec. 4 game at Colorado State, or his early substitution 51 seconds into the second half Dec. 21 against Utah. He returned to play 7½ more minutes in the 80-52 victory, but after his early exit against Cal Poly, sources said Dutcher sent him to doctors for testing.

The 6-foot-10 sophomore was on the bench in street clothes for SDSU’s next game, Jan. 1 against Fresno State, and has not practiced or accompanied the team on road trips since. Matt Mitchell replaced him in the starting lineup, and the seventh-ranked Aztecs have remained undefeated — at 18-0, the lone unbeaten team among the 353 in the NCAA’s Division I after Auburn lost Wednesday night.


A pulmonary embolism is a blockage in one of the arteries carrying blood from the heart to lungs, lowering oxygen levels in the blood and causing shortness of breath or chest pain — the most common symptoms. It can inflict damage to the lung’s tissues and be fatal if untreated.

In standard cases, the American College of Chest Physicians recommends a minimum of three months of anticoagulant medication, or blood thinners, to prevent more clots from forming while the body dissolves the current blockage, either by itself or with medical assistance. In rare cases, clot removal surgery is performed.

Patients are often cleared (and encouraged) to exercise after a few weeks, but only by themselves. Contact sports are out because of the increased chance of bruising and internal bleeding while taking anticoagulants.

Breaking up the blockage is just half of the medical equation. Doctors also must assess the cause of the clot, often delving into family medical histories, and determine steps to prevent recurrence.


Pulmonary emboli, or PE, are more commonly found in elderly, sedentary patients from deep vein thrombosis (DVT) — where a blood clot forms in the leg from sitting in the same position during long-distance flights, then travels to the lungs. According to UC San Diego’s Cardiovascular Institute, there are an estimated 600,000 U.S. cases each year of venous thromboembolism (VTE), the umbrella condition for PE and DVT.

But elite athletes are not immune, particularly in marathon runners and other endurance sports.

A 2017 study published in the Orthopaedic Journal of Sports Medicine tracked incidents of PE or similar clotting issues from 1999 to 2016 in 55 professional athletes from the NBA, NFL, NHL and Major League Baseball. The good news for Mensah: 85 percent eventually returned to play.

It just took a while. The study, led by physicians at Thomas Jefferson University Hospital in Philadelphia, found the average time away from playing was 6.7 months, although it varied based on the type and severity of the condition.


The study also discussed the potential impact of frequent travel, elevation and cold weather, since clotting incidents, research indicates, seem to occur more frequently during winter months. SDSU basketball players are exposed to all three during the Mountain West season, with a half-dozen road trips above 4,500 feet (and two above 7,000).

“High altitude is known to be a risk factor for developing VTE with increased levels of hypoxia and hemoconcentration,” the study said. “This is particularly meaningful for those athletes who train in places such as Denver, Colorado, where athletic stadiums are all located at elevations over 5,000 feet.”

Rashad Scott, a sophomore safety on SDSU’s football team from Helix High, told the Union-Tribune in October that he was diagnosed with a blood clot in both lungs last June after feeling a sharp pain in his left side. He was put on blood thinners for three months and played in the season’s final seven games, mostly on special teams.

In 2017, Aztecs offensive lineman Ryan Pope missed time from a similar issue and mentored Scott.


“It was just reassuring him that everything would be OK,” Pope told the Union-Tribune, “that it was a good thing he found it when he did. The longer you wait, the worse it gets. Catching it early was a blessing.”

Russell Okung, a Pro Bowl offensive tackle with the Chargers, experienced shortness of breath during an offseason workout in early June and was diagnosed with PE.

“They said, ‘You’re not leaving this hospital anytime soon,’” Okung told L.A. media last year. “And that’s when it kind of settled into me that this is serious. … I think (pulmonary embolism) is an ailment that a lot of players aren’t paying attention to and it’s becoming more prevalent as time’s going on. I think it’s something that a lot of players should start thinking about and checking themselves for.”

Okung returned to the field Oct. 27 — just under five months later — and played in six games.


Less fortunate were NBA players Chris Bosh and Mirza Teletovic, whose careers ended due to PE.

Bosh was admitted to the hospital shortly after the All-Star break in 2015, diagnosed with PE and ruled out for the remainder of the season. He returned the following season, only for the clotting to return a few months later. He never played again.

Teletovic retired in 2018 after a similar recurrence of PE and now, at age 34, is president of Bosnia and Herzegovina’s basketball federation.

Mensah has been seen shooting alone before or after practices. But if he indeed has been prescribed with blood thinners, he likely wouldn’t be cleared for any activities involving contact.


The Mountain West tournament begins March 4 in Las Vegas, or just over two months since his last game. The NCAA Tournament starts March 19 and lasts until April 6.

“A week after I got off my medicine,” Scott, the SDSU safety, said in October, “I was in Colorado with the team … feeling good as new.”