Carolina Panthers linebacker Thomas Davis will be suspended for the first four games of the coming NFL season after violating the league’s policy on performing-enhancing drugs.

Davis made the announcement on social media on Friday, calling it “one of the saddest days” of his career, while also stating “I am not a cheater”.

In the video posted with the message, Davis said: “I was completely caught off guard by this. I’ve never in any way done anything to try to intentionally cheat the game. It’s one of those situations where the NFL rules are clear; they state that you are responsible for what you put in your body.

“I’ve taken the same supplements for the last seven or eight years and never had any issues. Been tested numerous times over the years while taking the same stuff. And, unfortunately, these are some of the things that happens when you take supplements.

“I’ve never tested positive for a steroid or HGH. It’s not one of those situations. It ended up being an estrogen blocker that triggered a positive test for me. I just want you guys to know that in no way would I ever do anything, like I said, to cheat this game or to try to create a competitive advantage over anybody.”

The 35-year-old Pro Bowler, who was honoured with the Walter Payton NFL Man of the Year award in 2014, has missed only three games over the past six years.

Between him and Luke Kuechly, the Panthers have one of the best linebacker duos in the league and one that helped to allow the seventh-fewest yards last season with 317.1 per game.

While the NFL has yet to release the schedule for next season, Carolina will be tasked with playing in one of the toughest divisions as the NFC South featured three teams with at least 10 wins last year.

Davis had previously announced he would retire after 2018, but said in his video that the ban may change his plans.

“I’m going to serve this four-game suspension and I’ll be back ready to go back out there with my teammates,” he said. “And, you know, who knows? Maybe this isn’t my last year.”