Cleveland Browns wide receiver Antonio Callaway will miss the first four games of the regular season due to a suspension.  

An NFL spokesperson announced Callaway's four-game ban stems from a violation of the league's substance abuse policy. 

"I take full responsibility for my actions," Callaway said in the announcement. "I made a mistake and I own that. I have taken steps to make myself better and I appreciate the Browns standing by me and supporting me during this time. I know there's nothing I can say to regain trust; it will all be about my actions."

Browns general manager John Dorsey also issued a statement: 

"We're disappointed in Antonio. Freddie and I have had a direct conversation with him about where we stand. He understands our expectations of him. We will continue to support him as long as he remains committed to taking advantage of the resources made available to him by our club and the league to help him become the best version of himself as a person first and foremost."

Callaway has been a source of frustration for the Browns this preseason. Offensive coordinator Todd Monken told reporters on Aug. 1 the second-year wideout arrived to training camp out of shape. 

"To his credit—I shouldn't say his credit—hell, he came in a little bit out of shape probably," Monken said. "The last seven days, he's getting himself back in shape, putting himself in position. You can see that he's starting to feel more comfortable and make plays.''

Browns wide receiver coach Adam Henry told the media on Aug. 7 that Callaway was getting in better shape, but he was still working primarily with the second-team offense. 

Callaway had concerns coming out of the University of Florida last year. He failed a drug test during the NFL Scouting Combine due to a diluted sample. 

Cleveland selected Callaway in the fourth round with the 105th overall pick. The 22-year-old led the team with five touchdowns and ranked third with 586 receiving yards as a rookie. 

A four-game suspension will keep Callaway out until the Browns' Week 5 game against the San Francisco 49ers. Rashard Higgins and Jaelen Strong will likely compete to be the No. 3 receiver during training camp, with Odell Beckham Jr. and Jarvis Landry in the top two spots.