Indianapolis Colts Pro Bowl pass rusher Robert Mathis has been suspended without pay for the first four games without pay for violating the NFL performance-enhancing drug policy.

Mathis will be eligible to return to the Colts’ active roster on Monday following a Sept. 28 game against the Tennessee Titans.

"We have learned that Robert Mathis will be required to serve a four game suspension under the league’s policy on prohibited substances," the Colts said in a statement. "We recognize the extreme seriousness of this matter and will honor the confidentiality requirements of the league’s program. We nevertheless wish to assure Robert and our fans that he remains an honored and cherished member of the Colts family and that we support him as he deals with this difficult challenge."

Mathis issued a lengthy statement explaining his suspension.

"It is difficult for me to address the circumstances surrounding this suspension because they involve very personal medical information, but it is very important to me that my fans, particularly young people, understand what did and did not occur," Mathis said. "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. The union has worked very closely with me to present all of the facts and medical records for consideration of discipline that does not include a suspension because of the unique facts of my case, but the Commissioner refused the request.

"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. I hope that my fans will understand the unique circumstances involved here and continue to know that I am a man of integrity who would never intentionally circumvent the performance enhancing substance policy agreed to by the NFL and my union. The incredible blessing of this very upsetting situation is that, after I took the medication very briefly at the end of last season, we learned that my wife is expecting a baby. We are thrilled that we will be welcoming a new member in several months, but I apologize to my teammates, coaches and Colts fans that I will not be able to contribute to my team for the first four weeks of the 2014 season. I will work extremely hard during that time to stay in top football shape and will be prepared to contribute immediately upon my return.

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Aaron Wilson covers the Ravens for The Baltimore Sun