FILE - In this June 11, 2019, file photo, Oakland Raiders offensive guard Gabe Jackson (66) and teammates stretch during the NFL football team's minicamp in Alameda, Calif. The Raiders are concerned about the status of starting right guard Jackson after he injured his leg in a joint practice with the Los Angeles Rams. Jackson went down early in the session Thursday, Aug. 8, when someone rolled into his leg. Jackson was then taken off the field on a cart and owner Mark Davis went into the locker room shortly after that for almost 15 minutes. (AP Photo/Eric Risberg, File)

Oakland Raiders head coach Jon Gruden claps during NFL football training camp Thursday, Aug. 8, 2019, in Napa, Calif. Both the Oakland Raiders and the Los Angeles Rams held a joint practice before their upcoming preseason game on Saturday. (AP Photo/Eric Risberg)