Oscar Johnson, a former medical assistant for hockey’s minor league Utah Grizzlies, may have never met Derek Boogaard, the deceased N.H.L. left wing. But Johnson has agreed to plead guilty in a case involving painkillers he prescribed that may have ended up in the hands of Boogaard shortly before his death.

Johnson will plead guilty to one of the 27 counts he faced when he was indicted in September, according to a motion and a copy of the proposed agreement that his lawyer filed in United States District Court in Manhattan on Friday.

The count involves a single prescription for Percocet written by Johnson in 2009.

Johnson was indicted along with Jordan Hart, a former Grizzlies player who has been accused of selling pain pills to Boogaard.

If the deal is approved, other charges against Johnson will be dropped, the proposed agreement shows. The document, which is dated in January, indicates that both sides have agreed that the federal advisory guidelines call for a sentence in the range of 30 to 37 months.