The NFL on Monday will begin testing players for human growth hormone, according to NFL.com.

The league and the NFLPA announced Sept. 19 that the two sides agreed to a new drug policy that includes HGH testing for the first time.

NFL.com obtained a letter written by NFLPA president Eric Winston to players.

“As you know, the new Performance Enhancing Substances Policy includes hGH testing,” the letter read. “Testing for hGH will begin on Monday, October 6th. Each week of the season, 5 players on 8 teams will be tested. No testing will occur on game days. We negotiated to ensure that the methodology of testing be conducted in the most professional and safest manner for players. Importantly, after three years of negotiating, players won the right to challenge any aspect of the science behind the hGH isoforms test in an appeal of a positive test.”

The letter also stated that any substance abuse or performance enhancing drug policy violations, including HGH, will be handled by an independent arbitrator.

According to CBS Sports, other revisions to the drug-testing program include:

–Any appeal of a positive PED test (including HGH) will go in front of a third-party neutral arbitrator. Appeals will be processed more quickly than the former policy.

–Retroactive discipline for three specific players — Wes Welker, Orlando Scandrick and Stedman Bailey — makes each immediately eligible to return to their respective clubs.

–Discipline for violations of the PED policy (including HGH) will be modified. A first violation will be up to six games depending on the nature of the violation. Using diuretics or masking agents will result in a two-game suspension. Using steroids, stimulants, HGH or other banned substances will result in a four-game suspension. Attempting to manipulate a test will result in a six-game suspension.

–A second violation will result in a 10-game suspension.

–A third violation will result in a two-year minimum banishment.

–Testing positive for offseason banned stimulants will not result in a PED suspension; instead, the player will be placed in the substance abuse program.

–The commissioner will retain his current disciplinary authority in cases involving discipline for violations other than positive tests such as breaking the law.