Maxx Crosby posted a bittersweet goodbye to Raider Nation on Saturday ... but it looks like he's still in disbelief that his time in Las Vegas is ending.

The NFL star said, "I can't believe that this is a real thing. It's been 7 years being with the nation. Raider Nation has given me everything."

And he gave everything right back to the nation ... he was selected for the Pro Bowl 5 consecutive times while suiting up in silver and black. But, having ultimately fallen short of his goal of bringing a Lombardi trophy back to the Raiders, Crosby said he felt like he let the fans down.

Still, he called his 2021 season with the team, "the most fun" he's ever had playing football. It seems it's no coincidence that 2021 was also the only year he brought the team to the playoffs.

While it's hard to say goodbye, Crosby said he's looking forward to playing for his new team, the Baltimore Ravens, and has "zero ill will" towards the Raiders organization.

He said, "The whole city of Baltimore ... I'm coming in guns blazing. I'm going to be myself and I'm going to give everything I have in my heart and soul to be the best player I can possibly be, to help be the best leader, best example, on a daily basis."