New York Jets running back Le'Veon Bell took issue with the NFL's drug-testing protocol in a tweet Wednesday.

Bell noted he was given a random HGH test for the fifth time this season Wednesday and wrote that he refuses to partake in another:

The 27-year-old is in the midst of his first season with the Jets after he signed a four-year, $52.5 million contract during the offseason. In 10 games, Bell has rushed for 508 yards and three touchdowns, and caught 46 passes for 309 yards and a score.

The NFL began testing for HGH in 2014, and according to a 2016 article by Christian Red of the New York Daily News, the league's policy on performance-enhancing substances states that a player can be blood-tested up to six times in a calendar year, although there are exceptions if reasonable cause exists.

Bell was suspended for two games in 2015 as a member of the Pittsburgh Steelers for violating the NFL's Policy and Program for Substances of Abuse and then suspended for three games in 2016 for a similar violation.

He has never tested positive for a performance-enhancing drug, however.

Big things were expected of Bell in his first season with the Jets, but it has been a frustrating campaign for him and the team. After holding out all of last season in a contract dispute with the Steelers, Bell is averaging a career-worst 3.2 yards per carry.

Second-year quarterback Sam Darnold missed three games with mononucleosis, and his lack of progress has contributed to Bell's lack of production. The Jets are last in the NFL in yards per game (248.2) and 29th in points per game (16.4).

Bell and the 3-7 Jets are on a two-game winning streak, though, and they will look to make it three in a row when they host the Oakland Raiders on Sunday.