Robert Williams apparently is dealing with more than just a minor knee bruise.

The Boston Celtics rookie has an artery condition in both of his legs called Popliteal artery entrapment syndrome (PAES),’s Fred Katz reported Monday night, citing multiple sources.

For people with PAES, the muscles and tendons near their knees are positioned such that they compress the popliteal artery, the main artery that runs through and behind the knee. This compression restricts blood flow to the lower leg and can cause “aching pain, numbness, and tiredness or cramping in the calf” during exercise, according to the Cleveland Clinic.

Before C’s fans get too worried, though, a source told Katz the condition is “not too serious” and there are no signs Williams’ PAES is bothering him more than it has in the past. Williams has played with the condition for years, per Katz’s sources, and the Celtics were well aware of it when they selected him No. 27 overall in the 2018 NBA Draft.

The team reportedly will monitor the situation, however, as surgery is a possible form of treatment that could decompress the artery and improve blood flow.

Williams has missed two of the Celtics’ three games at the Las Vegas Summer League with a left knee contusion he suffered in his debut and also has been dealing with left knee tendinitis since last year, per Katz.

While these developments obviously are cause for concern, it doesn’t sound like any are serious injuries that would threaten Williams’ season or career. Boston also has a deep roster and can afford to be cautious with the 20-year-old rookie.

Thumbnail photo via Mark J. Rebilas/USA TODAY Sports Images