A trade back could help clear dead cap space off the books. Last year Dubas traded 25th overall for 38th overall to get rid of Petr Mrazek. A first round pick at 14 probably isn't going to provide any more chance at immediate help to the Penguins compared to a late first or early second (and quite frankly has about the same likelihood to work out in general), so it could be a move to help the current roster while still adding a decent prospect for the future.
Also, Dubas traded the Leafs' first rounder in 2018, 2019, 2020, 2021, 2022 and 2023, so a move is certainly possible.