Talk about a matchup nightmare. On the Kansas City Chiefs' opening drive, running back Damien Williams beat San Francisco 49ers defensive lineman Solomon Thomas in coverage for a 62-yard touchdown.

No, you did not read that wrong. No, it was not a typo.

Safety Jaquiski Tartt tried to make a play on Williams as he sped past Thomas and ended up knocking over the defensive lineman. Seeing Thomas in that situation probably confused a lot of fans.

49ers defensive coordinator Robert Saleh was asked on Monday about the play and what happened.

"You guys don't like Solomon on a running back?" Saleh jokingly asked reporters while laughing.

It seemingly wasn't the best use of Thomas' skillset.

"No, it's preseason," Saleh continued. "We're trying some stuff out. That could happen. With our system, when you're trying to bring five, when you're trying to bring six, when you're trying to bring overloads, somebody has to account for the back and usually it's going to be a defensive end. Otherwise, you're just rushing four all the time, or it's just a simple five-man pressure that's not very hard for offenses to pick up. So, you've got to be able to get creative and the more creative you get, the more you expose your linemen to coverage.

"On that particular play, that is not what we want. I'm glad it happened because it created a secondary check that we can get to and all that stuff. But it happened, I'm glad it happened. I'm not glad it happened, but you'd still like for us to get it down and get to the next play, but it was a great learning experience for everybody."

Saleh noted that pass rusher Dee Ford would have been the player in that situation during a regular-season game. Ford has not made his 49ers debut due to some knee tendinitis but is expected to be ready for Week 1. Saleh believes Ford is a solid player in coverage who has excellent awareness and speed.

Saleh went on to clarify that Thomas was supposed to cover Williams on that specific play.

Added Saleh, "He's, we call him a peel rusher, so that is his coverage. The overall design of the play, not what we want which is what I was referring to with Solomon being, basically him peeling with the quarterback being able to step into his throw is not something we want. So, no, we don't want that happening."