The Philadelphia Eagles will be missing one of their top special teams players for the first four games of the upcoming regular season.

Second-year linebacker Jake Knott was suspended without pay for the first four games for violating the NFL's policy regarding performance enhancing substances.

In a statement released by the team Friday, Knott attributed the positive test to a nutritional supplement he had been taking that contained a banned stimulant.

"Several weeks ago, I was shocked to learn that I tested positive," Knott said. "I have never knowingly ingested a banned substance, but like most players, I take nutritional supplements. Unfortunately, I now know that supplements are not regulated and thus may contained things that are not listed on the label."

Knott made the Eagles as a undrafted free agent last season from Iowa State.

His suspension does not take effect until the start of the regular season. He is eligible to participate in all offseason and preseason practices and games.

"The NFL policy is very strict, so I have chosen to take immediate responsibility," Knott said. "I look forward to participating in team workouts, training camp and the preseason with my team. During the suspension, I will work extremely hard to stay in top football shape and be ready to contribute immediately upon my return. I sincerely apologize to my teammates, coaches, my family and fans for the impact of my mistake on the team."

The 6-foot-2, 243-pounder missed four games last season with a strained hamstring, but was a key member of the team's kickoff and coverage unit. He also registered six tackles on defense as a backup inside linebacker.

He could have a tough time making the team this season. Among their offseason moves, the Eagles signed former Houston linebacker Bryan Braman during free agency to a two-year, $3.15 million contract with $1 million guaranteed. Braman was an alternate to the Pro Bowl last season.

"We're very disappointed to learn of (Knott's) suspension," the Eagles said Friday in a statement. "We have spoken to Jake, and he is fully aware of the mistake he made and owned it. The key for him, however, is to learn from that mistake and move forward with his preparation for the 2014 season."

Contact David Weinberg:

609-272-7186