The San Francisco 49ers offseason got off to a bad start with word that linebacker Reuben Foster was arrested in Alabama for marijuana possession. The charge is a misdemeanor and he’ll likely get off with a fine in court, but he faces some uncertainty in the NFL.

He likely faces a stiff fine, although a suspension could be a possibility depending on where he is in the league’s drug-testing program. But even if it’s just a fine, he could find himself losing out on guarantees in his contract.

First round picks generally get fully guaranteed or close to fully guaranteed contracts. According to Over The Cap, Foster’s contract is fully guaranteed through 2019, and his fourth year has $339,000 of his $1,697,124 base salary guaranteed. Last June, Ian Rapoport reported that it was an unprecedented amount of fourth year money guaranteed for a late first round pick. Normally they don’t get the fourth year guaranteed, but given the beliefs about Foster’s talent, the 49ers were willing to treat him like a higher pick.

Now, he stands a good chance of losing some or all of those guarantees. Two years ago, former agent Joel Corry was writing about how league discipline impacts guaranteed money. He said that, “Every NFL contract I’ve seen since the new CBA took effect in 2011 contains language voiding contract guarantees for an exhaustive list of defaults by the player.”

He talked primarily about suspensions, but it sounds like Foster could lose his guarantees. This does not mean he loses the money, but rather the guarantee that he would be paid that money even if he was released. If the guarantees do go away, the 49ers could release him at any point and not owe him a penny. The prorated signing bonus money would impact their cap, but they would not owe him further salary.

Ideally this does not actually become a situation the 49ers take advantage of during Foster’s career. I think most of us hope that this is the last of Foster’s trouble and he can just go back to being a productive football player. But the option could be on the table as we move forward through his career.