Pro Bowl linebacker Thomas Davis of the Carolina Panthers has been suspended for the first four games of the 2018 season after testing positive for a banned performance-enhancing drug, ESPN reports.

Davis, who had already announced he would be be retiring after next season, called Friday’s announcement one of the saddest days of his career.

“I was completely caught off guard by this,” the 35-year-old said. “I’ve never in any way done anything to try to intentionally cheat the game. 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…”

Davis said he was not trying to cheat when he took an estrogen blocker, the drug that triggered his positive test.

“Unfortunately, this is some of the things that happen when you take supplements,” he continued. “I’ve never tested positive for steroids or HGH. This is 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 to cheat this game or try to create a competitive advantage over anybody.”

The 14th pick in the 2005 NFL Draft out of the University of Georgia, Davis was selected to the Pro Bowl three consecutive years from 2015-2017.