The 34-year-old Harrison, suspended without pay, will be eligible to return to the Patriots' active roster following the team's Oct. 1 game against the Cincinnati Bengals. He acknowledged the suspension in a late Friday night conference call, admitting that he obtained human growth hormone but said that he had never taken steroids.
"I want to make it clear," Harrison said, "that never once did I take steroids. I did admit to the commissioner that I took a banned substance."
The league issued a statement late Friday night confirming that Harrison is suspended without pay for four games, effective immediately.
Harrison said that his actions stemmed from his desire to "accelerate the healing process" from his various injuries the past two seasons.
Wade Wilson, currently the Cowboys' quarterback coach and former NFL QB, reportedly also admitted to NFL officials that he received illegal drugs.
According to the New York Daily News, Wilson admitted receiving HGH while working for the Chicago Bears from 2004-06. Citing sources, the News said Harrison and Wilson were subjects of an investigation by the Albany (N.Y.) County District Attorney's
office into an Internet drug scam.
According to ESPN's Chris Mortensen, a law enforcement source said Harrison admitted he began using HGH two years ago to recover from injuries. The same source said prosecutors allowed an NFL security official to sit in on a conference with Harrison earlier in the week. At that time, Harrison made his admission and the official reported it to NFL commissioner Roger Goodell, which led to a Friday hearing.
Harrison used a Friday night conference call to apologize to team officials and to his teammates, and to caution young people against using performance enhancers.
"I've made no excuses and I will not make excuses," Harrison said. "I sent the wrong message with my actions. This is a mistake and this is something that I've done."
A Patriots source told ESPN.com's Len Pasquarelli that the team is aware of the sanction against the 13-year veteran and is "dealing with it." The team source declined to say when the Patriots became aware of Harrison's involvement.
League sources confirmed to ESPN and ESPN.com that at least one NFL assistant coach has also been questioned in recent months by investigators as part of the probe and faces disciplinary action because he also has been linked to HGH in the same investigation.
The admission by Harrison has not been made public, but his name was among those known to federal and New York officials conducting a large-scale investigation into an Internet pharmaceutical distribution ring for steroids and other performance enhancers, such as HGH.
The investigation was instigated by the Albany County district attorney, and involved New York Bureau of Narcotics Enforcement agents and an Orlando, Fla,-based federal task force. In February, state and federal agents and representatives from other law enforcement entities raided two Signature Pharmacy outlets in Orlando, and several Florida clinics alleged to have supplied prescriptions for performance enhancers to professional athletes.
Also, the owners of Applied Pharmacy Services in Mobile, Ala., which is alleged to have provided performance enhancing drugs to athletes, were indicted in Albany County.
As part of the Florida and Alabama raids, it is believed that investigators discovered the names of several athletes, but it is not known if Harrison was among them.
Earlier this year, Albany County district attorney David Soares said that he would provide the NFL, Major League Baseball and any other leagues the names of players believed to have made purchases through the alleged distribution ring.
NFL and Major League Baseball officials subsequently traveled to Albany to meet with Soares and other investigators.
The loss of Harrison would certainly be a blow to the Patriots, who have struggled each of the past three seasons with devastating injuries in the secondary. And it would be a setback for Harrison, who has been limited to only 13 games over the last two seasons because of serious injuries.
Coach Bill Belichick and vice president of personnel Scott Pioli have worked hard to build depth in the secondary unit, but their efforts seem to be annually undermined.
Harrison, 34, has begun to decline a bit, but is still regarded as one of the league's most physical safeties, and a leader on the New England defense. He signed with the Patriots in 2003 as a free agent, after being released by the San Diego Chargers, with whom he spent the first nine seasons of his career.
The four-game suspension will cost Harrison $470,588 of his scheduled 2007 base salary of $2 million.
It marks the second suspension of Harrison's career. In 2002, he was suspended one game by the league for a helmet-to-helmet hit on then-Oakland Raiders wide receiver Jerry Rice. Harrison has also been fined over $200,000 by the league for his aggressive play.
Information from ESPN.com senior writer Len Pasquarelli, ESPN NFL analyst Chris Mortensen and The Associated Press was used in this report.