I think that Mike Foligno was the captain of the Sabres when he
got traded to the Leafs. Also, wasn't Rick Vaive the captain of
the Leafs when he got traded to Chicago (with Steve Thomas for
Ed Olcyzk and someone). Speaking of the Leafs, I believe that
Darryl Sittler was their captain (he'd torn the "C" off his
jersey but I think he re-claimed the captaincy later on) when he
was traded to the Flyers.

Oh yeah, of course, Gretzky was the captain of the Oilers before
he was traded wasn't he?