That's because he wants a contract extension, and he and the 49ers remain far apart in the negotiations. The two sides have made no progress since before last month's draft,"Will the 49ers trade Brandon Aiyuk? The teams that checked on it got the sense that no, they weren't interested in doing it, and that's what they said as well.
"I'm guessing the 49ers would pay Aiyuk $25 million per season and he wants closer to $30 million per season. That would be a big difference. So if Aiyuk isn't willing to take the 49ers' offer, I think they'll let him play out his rookie deal, then franchise tag him next year and trade him for a second-round pick. That would be smarter than paying Aiyuk $30 million per season.