Indianapolis Colts defensive end Robert Mathis has revealed that his four-game suspension for using performance-enhancing substances was down to a fertility drug.
The 33-year-old will miss the first four games of the 2014 season after taking the drugs to help the expansion of his family, but the substance used was illegal in the eyes of the NFL.
Mathis said in a statement: "Like many families, my wife and I faced fertility challenges, and I sought medical assistance. I specifically asked the doctor if the medication he prescribed for me would present a problem for NFL drug testing, and unfortunately, he incorrectly told me that it would not.
"I made the mistake of not calling the NFL or NFLPA to double check before I took the medication at the end of last season.
"I am deeply saddened that this situation will prevent me from contributing to my team for four games, and I regret that I didn't cross check what my doctor told me before I took the medication."
Mathis recorded 59 tackles and 19.5 sacks in the 2013 season.
