I just checked -- the St Louis pick is top-10 protected. If St Louis gets a top-10 pick in 2019, Buffalo can't touch it and has to wait until 2020 to claim the pick. St Louis might be much better the following season, so that pick might be far less valuable.I agree, that's why I mention Weber and not Petry.
If we talk what Bergevin is likely to do, he won't trade either of them. He's likely to stick with status quo, maybe get a Drewiske or Campoli type...bottom 6 forwards...and let it play out. Regroup in summer.
The good news is it'll be easier for Buffalo to trade that pick, since it won't be a top-10 pick in 2019. Bad news is it'll be a total crapshoot where the Blues finish in 2019/20.