Minnesota Vikings defensive end Spencer Nealy was handed a four-game doping suspension by the National Football League on Friday for using a banned stimulant that he claimed was taken unknowingly.
The second-year NFL player was signed in 2013 as a reserve by the Vikings, who went 5-10 with one drawn last season, last in the National Conference's North division.
The league does not announce exact substances for which a player tests positive, citing US medical confidentiality laws.
Nealy will miss Minnesota's first four games of the upcoming 2014 campaign, including the September 7 opener at St. Louis, a home game against New England the following Sunday, a trip to New Orleans on September 21 and a September 28 home game against Atlanta.
While his first possible game would be October 2 at Green Bay, Nealy can participate in off-season and pre-season workouts and games.
Nealy, in a statement released through the players' union, said he ingested the stimulant in a tainted food supplement.
"I worked with my agent and the union to investigate the test results and I learned that a supplement I took contained a banned stimulant," Nealy said.
"I understand that the NFL policy is very strict and I take responsibility. I'm very sorry for the impact of this situation on my teammates, the Vikings organization and Vikings fans.
"I will work extremely hard during training camp and during the suspension. I will stay in top shape and will be ready to contribute upon my return."