Something is off with 49ers receiver Brandon Aiyuk this year. He says it’s because defenses are playing him differently. Some think it’s because his hold in lasted too deep into the preseason. Some might be wondering whether there are still issues with Aiyuk and the 49ers, even after Aiyuk got paid.

As to the last possibility, Aiyuk inexplicably showed up for practice on Friday in the wrong shorts. Coach Kyle Shanahan let him hear about it, and Aiyuk changed the shorts (from red to black) on the practice field.

After practice, Shanahan was asked if Aiyuk showed up in the wrong shorts.

“Yeah, he did,” Shanahan said. “Good question.”

Is it punishable?

“No,” Shanahan said. “I wish I could wear different shorts.”

Shanahan might wish he’d traded Aiyuk when he had the chance. As Jay Glazer of Fox reported several weeks ago, and as Shanahan basically confirmed, the 49ers were finalizing a deal to trade Aiyuk to the Steelers when Aiyuk decided to do a deal to stay in San Francisco.

Whatever is happening, it bears watching today. Aiyuk has 11 catches for 119 yards this season.