As mentioned though, Semien is on the wrong side of 30 now, while Bichette is still very young. Semien was a better defensive SS previously but will he be over the next 3-5 years? Another factor is that Bichette wants to be a SS, and the Jays, if they want any chance of extending him, have to consider his wants to some degree (unless he becomes 2019-2020 Vlad, then you just make the move and tell him to be quiet). If the Jays re-sign Semien, and Bo agrees to moving off SS, then that's another story, but I don't see that happening, and if Semien would prefer moving back to SS, then coming back to the Jays becomes a little less of a priority especially if the offers are similar elsewhere.