Indianapolis Colts linebacker Robert Mathis has been suspended without pay for the opening four matches of the 2014 regular NFL season.
The ban relates to a violation of the league's policy on performance-enhancing substances and will mean that Mathis misses games against the Denver Broncos, Philadelphia Eagles, Jacksonville Jaguars and Tennessee Titans.
The 33-year-old will be eligible to return to the active roster on September 29 ahead of the meeting with the Baltimore Ravens, while he is also free to participate in all off-season and pre-season activities.
"We have learned that Robert Mathis will be required to serve a four game suspension under the League's policy on prohibited substances," read a statement from the Colts.
"We recognise 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, who has been with the Colts since being chosen in the fifth round of the 2003 Draft, reached his sixth consecutive Pro Bowl last season.
