Shaw played a lot of 2nd for them last season, and could move there permanently if they signed Machado. They definitely need another infielder. They have a gaping hole at either 3B or 2B, and their window is now, though SP is probably a bigger need than another bat.
As for the Twins - you're right, they've never handed out a contract like this. But neither have the Sox. The Twins have $0 committed to 2020 payroll. They definitely have the money to sign Manny Machado.