Tennessee Sen. Bob Corker withdrew himself Wednesday from consideration as a possible running mate for Donald Trump.

The surprise move comes as sources had told CNN Corker was being “very seriously” vetted by the Trump campaign.

But Corker, who is chairman of the Senate Foreign Relations Committee, told CNN he is instead open to serving in Trump’s cabinet, perhaps as secretary of state, and will speak at the Republican convention later this month.

“I feel like I’m better suited to other kinds of things and I think there are probably better suited people for this particular job for now,” Corker told CNN on Capitol Hill.

Corker declined to say whether he and Trump had discussed particular positions in a Trump administration. “I don’t want to get into that so much,” Corker said.

Translation: “I spent some time with Trump yesterday and the guy is batshit insane and I don’t want to campaign with him because I want a political career that goes past November.”