The Leafs are in a position at the moment where they're sitting $1.493M above the salary cap and they'll need to move a body out to be able to afford to sign young Rasmus Sandin to a new contract. This is where Justin Holl comes to mind.
Holl, 30, is only one year older than John Klingberg and is just as valuable on the special teams as the 2018 All-star is, albeit for a different reason. Where Klingberg excels on the power play, Holl excels on the penalty kill. Holl also carries a cap hit of just $2M, which is definitely affordable for most teams. Though his offensive output is not be nearly as good as Klingberg's, Holl is still an intriguing piece that can slot into a team's top-four right away and onto their top penalty killing unit as well. In addition, his exceptional rush defense could be a welcome addition to any team who has a specific thorn in their side within their division who they're looking to try to shut down from the rush.
Trading Holl won't be an easy thing for GM Kyle Dubas, who oversaw the development of the 30-year-old blueliner, but after the signings of Jordie Benn and Victor Mete it is something that will likely happen. Holl has been a big part of Toronto's defense corps since he was signed in 2017-2018, but the silver lining in a Holl trade is that it will give the Leafs just enough cap space to get Sandin locked up to a new deal, removing any concerns of a potential offer sheet and it will get us one step closer to a finalized 2022-23 roster.