All the Bruins top defensive prospects are left handed, but Zboril and Lauzon have experience playing both sides (Lauzon has only played RD in the NHL).
Vaakaneinen - Expansion draft exempt. Excellent skater and puck mover that thinks the game very well. High floor. Plays conservative. Its unclear if he will ever develop offense to raise his ceiling beyond a 2nd pairing puck mover. NHL ready.
Zboril - Has played the shutdown role in Providence for a couple years and by the end of the year was the teams best defender and was starting to look like the guy they thought they drafted. The pros are that he is a smooth skater and puck mover and also has jam and nasty. The con is that he has a history of making the selfish play (going out of position for the big retaliatory hit) and that he has to go thru waivers. NHL ready.
Lauzon - Modern physical defensive defenseman. He is good at getting a low hard shot on net, but that's it for offense. Can play both sides and Boston was using him at RD with Gryz for the last third of the season.
Other guys of interest -
Beecher - just finished his freshman season at Michigan. Big and fast. Think Ryan Kesler. Does the offense develop like it did with Kesler?
Bjork - just signed at 3 yr 1.6m deal. Speedy two way winger that can play both wings. He was very good at getting in scoring positions and LOOKED like a 2nd liner, but just no finish. Is that it or is there more? At a minimum, you have a cost controlled NHL player with versatility.
Frederic - Mean f***ing SOB. Big and strong. Has some playmaking skills and for a while was leading AHL in posts hit. You hope you are getting a Boone Jenner.
Senyshyn - Poor guy. Will never be Barzal or Connor or Boeser or...well... can go on and on. What he is is a big and fast straight line skater that is good on the forecheck and will head to the net. Bruins have been playing him in the bottom 6 in Providence in a checking line role to have him work on his all around game, since in the OHL he was basically a break away cherry picking specialist. No way to put lipstick on it, despite looking good in his three NHL games, he has not lit it up in the AHL. A change of location would be good for him. Would be a throw in, but I think he is worth mentioning as someone who could fill in on the right side in the bottom 6 for cheap.