Willi's projected arbitration salary was $1.7 million for 2023. It's also possible that Harris was given the indication from Hinch and staff that Willi was never going to get it.
Additionally, the Tigers hitting staff might not have unlocked what the Twins did. Harris saw the projected salary for tendering Willi and decided to go with someone else. This is a small move IMO and I'm not going to kill Harris for it.