Photo: John Hefti (AP)

Raheem Mostert left Thursday night’s totally awful and pointless contest between the 49ers and Raiders in the third quarter, after he was tripped on an inside run, tried to brace his fall, and had his right forearm bend in several wrong directions. This video is extremely unpleasant:

Possibly the worst part is hearing Mostert screaming in pain while he writhes on the ground. I am amazed that he was able to stand up and walk off the field without wailing like a professional mourner. Mostert was working on a nice game, with 86 yards and a score on just seven carries. Kyle Shanahan says he “would assume” Mostert is out for the season with a broken arm. I think we can cut past the assuming! Healthy arms do not have more than one elbow.