Talib, who tested positive for Adderall, will not appeal the suspension, which will begin Sunday when the Bucs take on the Chiefs in Tampa.
"Around the beginning of training camp, I made a mistake by taking an Adderall pill without a prescription," Talib said in a statement. "This is especially regrettable because, for the past several months, with coach (Greg) Schiano's help, I've worked very hard to improve myself -- professionally and personally -- as a player and a man.
"I am truly sorry to my teammates, coaches and Buccaneers fans, and I'm disappointed in myself. I will work diligently every day of this suspension to stay in top football shape and be ready to help this team in the second half of the season.
"I have chosen to be immediately accountable for the situation I put myself in, which is why I will not exercise my appeal rights and will begin serving the suspension immediately."
"We are disappointed to learn that Aqib Talib will be suspended for four games, which will begin with our game tomorrow against Kansas City," Schiano said in a statement. "I have spoken with Aqib, and he knows that he made a poor decision that let our team down. Certainly, other players will have the opportunity to step up while he serves this suspension."
Adderall is a white-hot drug around the NFL these days. We've seen numerous players (Joe Haden of the Browns comes off his Adderall-related suspension this week) suspended this season for using the attention-deficit-disorder drug.
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