Teófimo López lost to George Kambosos Jr. last week via split decisions and subsequently dropped the WBA (Super), IBF, WBO and The Ring Magazine lightweight titles.

But one doctor told ESPN Saturday that López could have lost even more.

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Teófimo López knocks down George Kambosos in the 10th round during their championship bout for Lopez’s undisputed lightweight title at The Hulu Theater at Madison Square Garden Nov. 27, 2021 in New York, New York.

Teófimo López knocks down George Kambosos in the 10th round during their championship bout for Lopez’s undisputed lightweight title at The Hulu Theater at Madison Square Garden Nov. 27, 2021 in New York, New York. (Al Bello/Getty Images)

"He could have died, for sure," Dr. Linda Dahl told ESPN. "How he breathed, I can't even explain to you. It's like somebody tied a 300-pound set of weights around his chest ... like his neck and chest were in a vise. That's how he fought."

Dahl, who reportedly reviewed Lopez’s medical records, told the outlet the former champion boxer was diagnosed with "pneumomediastinum" and had "extensive air in the retropharyngeal space." According to Johns Hopkins, pneumomediastinum is a "condition in which air is present in the mediastinum (the space in the chest between the two lungs). This can be caused by a traumatic injury or in association with pneumothorax or other diseases."

Dahl said there were pockets of air around his chest, heart and neck. She said if he was hit in the neck or chest in an awkward way, he may have suffered a collapsed lung.

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Teófimo López bleeds from a cut over his eye against George Kambosos during their championship bout for Lopez’s undisputed lightweight title at The Hulu Theater at Madison Square Garden on Nov. 27, 2021 in New York, New York. 

Teófimo López bleeds from a cut over his eye against George Kambosos during their championship bout for Lopez’s undisputed lightweight title at The Hulu Theater at Madison Square Garden on Nov. 27, 2021 in New York, New York.  (Al Bello/Getty Images)

She said the condition may have been caused by a small tear in his esophagus. According to ESPN, López started to have shortness of breath before the weigh-in, but he said he thought it was just asthma. He tested positive for COVID-19 in June.

López said he "fought through asthma before" and was worried if he divulged it the fight may have been canceled. He said things took a turn for the worse after the weigh-in when he and his team went to dinner.

"I took a seat in the back of the restaurant by the kitchen. Everybody's trying to burp me and relax me. They see my neck is swollen. My voice changed. At this point, everybody's a little concerned. I think my dad told me I should go to the hospital, and I said no because they're going to end up probably canceling the fight," Lopez told ESPN.

George Kambosos punches Teófimo López during their championship bout for Lopez’s undisputed lightweight title at The Hulu Theater at Madison Square Garden Nov. 27, 2021 in New York, New York.

George Kambosos punches Teófimo López during their championship bout for Lopez’s undisputed lightweight title at The Hulu Theater at Madison Square Garden Nov. 27, 2021 in New York, New York. (Al Bello/Getty Images)

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The hampered boxer was then put on the ground by Kambosos en route to his defeat. Lopez’s team reportedly called Dahl on Monday to get checked out quickly, and the doctor said Lopez was just lucky to be alive. She was baffled how he fought with the air in his chest.