The Boston Celtics are unsure when Isaiah Thomas first suffered the labral tear in his hip. 

While the Celtics didn't reveal the injury until Thomas was ruled out for the season during the Eastern Conference Finals, many look back to a collision he had on March 15th with Karl-Anthony Towns.

Thomas could have even suffered the injury on December 5th, which forced him to miss four games over 10 days. The injury was listed as a groin strain at that time, which is actually a common belief for this type of injury.

"Very likely," said Dr. Carlos Guanche about Thomas actually suffering the labral tear in December. Guanche has performed more than 3,000 labral-tear repairs in his 20-year clinical career. "I wish I had a dollar for every patient that has told me, 'I've been treated for a groin strain for the last X days, weeks, months, year or whatever,' and it turns out to be a labral tear."

Hip specialist Dr. Marc Philippon hasn't seen Thomas, but he believes Thomas could make the injury worse over the long-term by not undergoing surgery. Philippon has performed nine of the 13 surgeries to repair a torn labrum on the hips of NBA players.

"If it's a contract year, I understand that," Philippon says. "But if you play with a bad hip and you end up having a bigger problem, I'm not sure how good the contract is going to be."

Thomas will be a free agent this offseason after signing a four-year, $27 million deal with the Phoenix Suns in 2014.