Diehl was charged with DUI after hitting several parked cars with his BMW on Sunday night.
DUIs fall under the substance abuse policy, and the league and union are still operating under the terms of the 2010 substance abuse policy, and will until the parties reach agreement on a new drug policy that includes HGH testing.
A league source reiterated Tuesday what Pro Football Talk earlier reported -- that the NFL has been trying to increase the discipline for DUIs for several years. NFLPA spokesman George Atallah declined comment, but he acknowledged that discipline for DUIs is up for negotiation as part of the substance abuse policy.
The current policy states a first DUI results in a fine of a game check, up to a maximum of $50,000, with subsequent violation leading to further discipline, which can include suspensions.