No one outside of the 49ers and Colts' front offices saw the DeForest Buckner trade coming last month.
Not even one of Buckner's best friends, Arik Armstead.
Buckner and Armstead, who played together seven of the last eight years between the Oregon Ducks and 49ers, are very close.
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Still, Armstead, who signed a long-term contract with the 49ers the same day Buckner was traded, was caught off guard.
"I didn't have any knowledge of it, so I signed and then I heard of that, so it was a shock to me," Armstead said on KNBR 680's "Papa and Lund" show Thursday.
The 49ers traded Buckner to Indianapolis for the No. 13 overall pick in this month's NFL draft. It was a stunning move considering Buckner's place in the 49ers' locker room.
"It was a shock. You know, I was confused and I didn't really expect that," Armstead said. "Super excited and happy for him. Me and him actually have been working out for a few weeks now, so we've been able to hang out and talk about it. God works in mysterious ways and we both believe things happen for a reason. It's going to be weird not playing alongside each other anymore like we have done for about eight years, but I know he's going to do amazing things up there with the Colts. I'm super happy for him."
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Filling Buckner's shoes will be a tall task. The 49ers have in-house candidates, like D.J. Jones, or they could use their second first-round draft pick, No. 31 overall, on a defensive lineman like Iowa's A.J. Epenesa.