Quoting: ON3M4N
The closest comp I can think of is Mark Stone. Now Stone is a more complete player than Hertl, but centers are a premium in the NHL so we'll call it even (still slight edge to Stone IMO though). in 2019 Stone was traded for:
Oscar Lindberg - 27yr old career 4th liner
Erik Brannstrom - 15OA pick in 2017 NHL Draft - Smaller LD that projected at worst as a top 4 d-man
2020 2nd round pick (DAL) - ended up being the 2nd to last pick in the round
IMO, a better comp would be the 2nd Matt Duchene trade between Ottawa and Columbus.
Unlike Stone, both Hertl and Duchene are very similar type of players, both play the same position, same cap hit and are/were pending UFAs.
What Ottawa got in the 2nd Matt Duchene trade was a 1st round pick, two middling prospects and a conditional 1st that never materialized.
I think something like that in a trade between Boston and San Jose over Tomas Hertl is more than fair for both sides.
Within the last week, I proposed a trade where San Jose is arguably getting a return on Hertl from Boston than Ottawa got on Duchene from Columbus.
I also used a rough template for what Kevin Kurz said was what the Sharks wanted for Hertl.
And of course, I took a lot of heat for it
https://www.capfriendly.com/armchair-gm/team/2782868
https://www.capfriendly.com/armchair-gm/team/2783152
https://www.capfriendly.com/armchair-gm/team/2789145