Why the 49ers are Down on Brandon Aiyuk

He's missing time, which is causing him to miss assignments and run the wrong routes. Which means he's not prepared.

We're starting to learn why Brandon Aiyuk's stock is down.

It seems the 49ers don't feel he's reliable right now. He's missing time, which is causing him to miss assignments and run the wrong routes. Which means he's not prepared.

"Anytime you have a setback with a hamstring," Kyle Shanahan said Wednesday, "and you have a guy behind you playing as well as Trent (Sherfield) has played -- I know Trent wasn't a first-round draft pick, so that might be not be as obvious with the talent level, but he has been a hell of a football player since he has been here. Aiyuk has been a little inconsistent since he has been in and out with his injury. Aiyuk still has a chance to get that spot and not rotate as much. Trent just doesn't make that very easy. I'm happy with Aiyuk. It's nothing against Aiyuk. I'm just also happy with Trent, too. I think both of them can get better."

"Where does Aiyuk need to get better?" a reporter asked.

"It's like every player," Shanahan said. "You have to grow in every single area. I know it seems like we're punishing Aiyuk because Sherfield got even reps with him or we rotated those guys. I'm not going to say Aiyuk has to do A, B and C to get back out there. It's more that we've been practicing the last month and one guy has been there every day and the quarterback has a lot of confidence in him. I do. If he wants to be out there every play, he has to be a lot better than the guy behind him."

Translation: Both Shanahan and Jimmy Garoppolo currently prefer Sherfield over Aiyuk. That's obvious.

Here's what Garoppolo said Wednesday about Sherfield:

"As a quarterback, when you have a receiver that you know where he's going to be and when he needs to be there, it puts your mind at ease. You're thinking about a million things as it is. If you could cut one of those things out, it makes for a lot easier of a play. Those little things go a long way in a quarterback's eyes."

As you may remember, Garoppolo threw an interception in the preseason that tipped off Aiyuk's hands. Perhaps Garoppolo thought Aiyuk ran the wrong route and wasn't at the right place at the right time.

Sounds like Aiyuk has quite the hill the climb.