According to Branch, police took Foster into custody at the Grand Hyatt Tampa Bay at 9:10 p.m. ET and formally booked him at 11:11 p.m. ET.
The 49ers are staying in Tampa ahead of Sunday's game against the Buccaneers.
The Athletic's Greg Auman shared Foster's mugshot:
Foster served a two-game suspension earlier this season as the result of a misdemeanor weapons charge and a misdemeanor charge of marijuana possession in separate incidents. He had pleaded no-contest to the former and saw the latter dropped by prosecutors.
Foster was also the subject of a domestic violence investigation earlier in the year.
The Santa Clara County, California, District Attorney's Office announced in April it had charged Foster with felony domestic violence, saying he struck his then-girlfriend, Elissa Ennis, eight to 10 times, which left her with a ruptured eardrum.
Shortly after the charges were announced, 49ers general manager John Lynch released a statement to say the team was going to wait for the results of the investigation and subsequent trial before making a final decision on Foster.
"We do feel like patience is the right approach right now," Lynch said. "We're going to learn things through this legal process. But I want to be abundantly clear, if these charges are proven true, if Reuben did hit this young lady, he won't be a part of this organization going forward."
Ennis ultimately testified that Foster hadn't hit her and the injuries she had were the result of a physical altercation with another woman. Ennis told the court the allegations were part of a "money scheme" and that she "wanted [Foster] to go down."
Because of Ennis' testimony, the judge in the case dropped the domestic violence charges against Foster in May.
Foster, a 2017 first-round draft pick, has appeared in six games this season.
Regarding his most recent arrest, Branch wrote 49ers officials "were unavailable for comment."