Shanahan explains what goes into playing his starters in the preseason finale

As more teams participate in joint scrimmages, they’ve strayed away from playing their starters during the preseason. Brock Purdy played nine snaps in Week 2. Fred Warner, Charvarius Ward, and Talanoa Hufanga saw the field for two series, but it amounted to 12 snaps.

49ers head coach Kyle Shanahan made it clear that Brock Purdy and the starters would play in the preseason finale after Saturday’s win over the Denver Broncos. On Tuesday, Shanahan explained his thought process in playing the first-team this Friday against the Chargers:

“It’s all about having guys ready to play a real football game. And there’s so much that goes into mentally being ready, physically being ready. I mean, you can’t have any hesitation in this game.

When Week 1 starts, people see that, and you can lose games very fast just being a little bit off. You kind of build that with experience over your career, but I’ve had guys that I’ve sat for the whole preseason games and then fumble their first play that they get in, and then you kick yourself in the butt for it. It’s just like, ‘what was I doing?’

You’ve also played guys and they get hurt and you’re like, what the hell was I thinking? So, there’s zero absolutes in any of it. That’s why I don’t sit here and tell you guys what we’re doing way in advance. I look at each thing day to day. I look at our practices, I look at our reps, I look at the individual how he is and where he’s at in his career, how he is just with the week and where he is in terms of being ready for Week 1.

All that stuff goes into it and you don’t really know until it’s over what the right decision was. So, that’s why it’s not always fun to make those decisions. But I also know when you just sit everyone and you don’t practice football, you do your guys a pretty big disservice.”

There’s little incentive to play a player like Trent Williams or Christian McCaffrey in the preseason. There are no questions with those types of superstars. But, when you look at the defensive side of the ball, even players like Warner and Hufanga could use the reps, as you generally don’t take players to the ground in practice.