OWINGS MILLS, Md. -- Baltimore Ravens running back Kenneth Dixon was suspended for the second time in six months Friday, when the NFL announced he is banned for an additional two games for violating the league's substance abuse policy.

His latest suspension will start after the conclusion of a four-game ban, which was issued in March after he violated the NFL's performance-enhancing drug policy.

Kenneth Dixon had a promising rookie season in 2016, but his suspensions and injury history could put his role with the Ravens in question. Rob Carr/Getty Images

Dixon will serve his suspensions while on injured reserve this season, meaning he will not have to miss additional games when healthy but will lose $190,588 in pay for the six games. He suffered a season-ending knee injury just before the start of training camp in late July.

The Ravens could question whether they can count on Dixon going forward considering his recent suspensions and injury history. Dixon, a fourth-round pick in 2016, had a promising rookie season in which he ran for 382 yards and two touchdowns. He was expected to compete with Terrance West for the starting running back job.