NASHVILLE, Tenn. -- Tennessee Titans left tackle Taylor Lewan is facing a suspension after a test came up positive for the banned substance ostarine, according to a post he made via social media Wednesday.

Thank you to everyone who sees this video and supports me. My family and I are so grateful to the Tennessee Titans organization and fans for your support. I will post the polygraph information next. #NoBadDays pic.twitter.com/lE9iEMmLxw

— Taylor Lewan (@TaylorLewan77) July 24, 2019

A source told ESPN's Adam Schefter that Lewan's A sample tested positive this summer but that the results of his B sample had not come back yet. If the samples match, he would face a four-game suspension.

Lewan, who can dispute the test results in an appeal, said he didn't knowingly use a banned substance.

"I've never taken anything that would cheat the game. I'm so sorry to the Tennessee Titans," Lewan said before pausing, taking a deep breath and wiping his eyes. "I'm sorry to the Titans, to the fans, that I won't be there for four games. I've never cheated myself, and I never want you guys to feel cheated. And I'm sorry. But I'm going to be better for this. I'm going to come back."

Lewan also posted apparent polygraph results on Instagram, and he said his supplements were tested by a third party.

He became the league's highest-paid offensive lineman last season after signing a five-year, $80 million deal that included $50 million guaranteed.

The Titans open up the season with a tough stretch of games that includes the Browns, Colts, Jaguars and Falcons.