You never know on the WS. I wouldn't bet on it, but crazy things happen in the playoffs.
Also, Correa is in charge of his own contract, IF (BIG IF) he really loves it in MN, he might play it out another year when the free agent SS market isn't as filled with big stars. If he waits until after next season, he'll still get a big contract without having to compete with Xandar Bogarts, Trea Turner, Tim Anderson, and more for the top contracts, and he still would probably have the highest AAV.
So, no to the trade. If you think you're getting to the playoffs, you're not trading your starting SS just because he might opt out.