Dallas Cowboys quarterback Dak Prescott smiles while warming up before the team's NFL preseason football game against the San Francisco 49ers in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Josie Lepe)

Dallas Cowboys owner Jerry Jones, right, stands behind quarterback Dak Prescott (4) as player warm up before an NFL preseason football game against the San Francisco 49ers in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Josie Lepe)

Dallas Cowboys running back Tony Pollard, center, carries against the San Francisco 49ers during the first half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

Dallas Cowboys quarterback Dak Prescott looks for a receiver during the first half of the team's NFL preseason football game against the San Francisco 49ers in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Jeff Chiu)

Dallas Cowboys wide receiver Michael Gallup (13) is tackled by San Francisco 49ers linebacker Dre Greenlaw during the first half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Jeff Chiu)

Gilroy (Calif.) Pop Warner football players observe a moment of silence for victims of shootings in Gilroy; El Paso, Texas; and Dayton, Ohio, before an NFL preseason football game between the San Francisco 49ers and the Dallas Cowboys in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Jeff Chiu)

A San Francisco 49ers cheerleader kneels during the national anthem before an NFL preseason football game between the 49ers and the Dallas Cowboys in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

Dallas Cowboys coach Jason Garrett, center, stands next to quarterback Dak Prescott (4) as they observe a moment of silence for victims of the shootings in Gilroy, Calif.; El Paso, Texas; and Dayton, Ohio, before an NFL preseason football game between the San Francisco 49ers and the Cowboys in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Jeff Chiu)

San Francisco 49ers quarterback Nick Mullens drops back to pass against the Dallas Cowboys during the first half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

San Francisco 49ers running back Raheem Mostert, left, tries to get away from Dallas Cowboys linebacker Leighton Vander Esch (55) during the first half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

Dallas Cowboys quarterback Dak Prescott (4) stands behind center during the first half of the team's NFL preseason football game against the San Francisco 49ers in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Jeff Chiu)

San Francisco 49ers quarterback Nick Mullens (4) looks for a receiver during the first half of the team's NFL preseason football game against the Dallas Cowboys in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Josie Lepe)

San Francisco 49ers offensive tackle Shon Coleman, center left, is helped onto a cart during the first half of the team's NFL preseason football game against the Dallas Cowboys in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Josie Lepe)

Dallas Cowboys coach Jason Garrett gestures while talking to an official during the first half of the team's NFL preseason football game against the San Francisco in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Josie Lepe)

Dallas Cowboys quarterback Cooper Rush (7) throws a pass against the San Francisco 49ers during the first half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

San Francisco 49ers tight end Levine Toilolo (83) is tackled by Dallas Cowboys defensive end Dorance Armstrong (92) and outside linebacker Leighton Vander Esch (55) during the first half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

Dallas Cowboys tight end Blake Jarwin (89) runs in front of San Francisco 49ers cornerback Greg Mabin (30) and linebacker Dre Greenlaw (57) during the first half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

San Francisco 49ers wide receiver Jalen Hurd (17) scores against Dallas Cowboys cornerback Donovan Olumba during the first half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Josie Lepe)

San Francisco 49ers quarterback Jimmy Garoppolo, left, stands on the sideline during the first half of the team's NFL preseason football game against the Dallas Cowboys in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

San Francisco 49ers quarterback Nick Mullens throws a pass against the Dallas Cowboys during the first half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

San Francisco 49ers wide receiver Jalen Hurd, center, celebrates with teammates after scoring against the Dallas Cowboys during the first half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

Dallas Cowboys linebacker Luke Gifford, second from right, is helped off the field during the first half of the team's NFL preseason football game against the San Francisco 49ers in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Josie Lepe)

San Francisco 49ers offensive players huddle during the first half of the team's NFL preseason football game against the Dallas Cowboys in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Josie Lepe)

San Francisco 49ers coach Kyle Shanahan watches during the second half of the team's NFL preseason football game against the Dallas Cowboys in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

San Francisco 49ers quarterback C.J. Beathard (3) rolls out during the second half of the team's NFL preseason football game against the Dallas Cowboys in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

San Francisco 49ers' Austin Walter carries against the Dallas Cowboys during the second half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

Dallas Cowboys running back Darius Jackson (26) runs between San Francisco 49ers' Damontre Moore, left, and LaRoy Reynolds during the second half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

San Francisco 49ers wide receiver Jalen Hurd celebrates after scoring against the Dallas Cowboys during the second half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Josie Lepe)

San Francisco 49ers wide receiver Deebo Samuel, top, catches a pass over Dallas Cowboys cornerback Michael Jackson during the second half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/Josie Lepe)

Dallas Cowboys running back Mike Weber (40) is tackled by San Francisco 49ers free safety Adrian Colbert during the second half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

San Francisco 49ers quarterback Jimmy Garoppolo, left, smiles on the bench next to quarterback Nick Mullens during the second half of the team's NFL preseason football game against the Dallas Cowboys in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

San Francisco 49ers' Brandon Wilds is tackled by Dallas Cowboys' Justin Phillips during the second half of an NFL preseason football game in Santa Clara, Calif., Saturday, Aug. 10, 2019. (AP Photo/John Hefti)

Dallas Cowboys defensive end Taco Charlton (97) rushes against San Francisco 49ers offensive tackle Shon Coleman (78) during a 2019 NFL week 1 preseason game, Saturday, August 10, 2019 in Santa Clara, Calif. The 49ers defeated the Cowboys, 17-9. (James D. Smith via AP)