San Francisco 49ers head coach Kyle Shanahan spoke to the media on Monday and gave injury updates on numerous players, including rookie linebacker Reuben Foster. Shanahan said the tests run on Foster on Monday all came back negative.

"Reub is alright," Shanahan said. "Should be good to go. We'll recheck it tomorrow but he was real sore today but MRI and the X-rays were ok -- or negative."

Foster left Sunday's 40-10 blowout loss to the Dallas Cowboys in the second half of the game after suffering a rib injury during a tackle of Ezekiel Elliott. He was examined by the 49ers medical staff in the locker room and was cleared to return but, with a victory out of reach, head coach Kyle Shanahan opted to keep the rookie linebacker out of the game.

"I know he wanted to go back in the game and he was cleared to go back in the game late in the fourth but that was me," Shanahan told reporters following Sunday's loss. "I held him out just at the end. It was too important. I wanted to make sure we had him next week. The fact that he was good to go there, I'm assuming he'll be good to go next week but you never know."

Ian Rapoport of NFL Network first reported that the injury to Foster was not too severe. He stated during an interview on KNBR that Foster's ribs were bruised and not broken and the rookie "should be ok."

In April, Foster was the second of two first-round draft picks by the 49ers. San Francisco selected him with the 31st overall pick after selecting defensive lineman Solomon Thomas third overall.

Cornerback K'Waun Williams, who suffered a quadriceps contusion, is not likely to play on Sunday against the Philadelphia Eagles, according to Shanahan. Right tackle Trent Brown is in the concussion protocol this week. Right guard Brandon Fusco, who had a biceps injury, is questionable.

"We probably won't know that all week," Shanahan said of Fusco. "I know he's got a chance but we're going to have to see how he recovers from rehab throughout the week. But he does have a chance."

Due to the injury to Williams, Shanahan said the 49ers might look into bringing back veteran defensive back Leon Hall, who spent nine days with the team earlier this month.

The 49ers will begin preparing this week for the Philadelphia Eagles, which they face on October 29.