Because the offense was so atrocious in the previous 2 matchups with SF (while the defense played well). Dallas stopped SF two drives in a row after the opening score, then the offense turned the ball over in SF redzone. The defense took the ball away from McCaffrey. Then the offense went 2 yards in 3 plays and punted AGAIN from deep in their endzone. Four drives about 3:30 in time: ZERO first downs, ZERO points, ZERO complimentary football AGAIN vs this same team. The defense does not get a huge pass, BUT if Dak and the offense cannot get anything going vs SF-there is zero reason to keep Dak on the team (and there are questions about the direction of the team and ultimate objectives of the squad moving forward).