Well, you have to consider that this isn’t he 2016-17 version of Sekera, who was a bonafide #2 defenceman who was solid in all three zones. 2017-18 Sekera looked old, immobile, and inept both offensively and defensively. His negative value right now would somewhat offset Puljujarvi’s value, and 39th overall is... eh?
My guess is you’d be looking more in the Severson+ or Demers+ tier of defenceman. Maybe a Pysyk+.
Just Puljujarvi and a 2nd would have more value than attaching Sekera’s contract at the moment. The smarter move is to give the shinpad assassin a full offseason to train and get the strength in his leg back, and hope he rebounds. He was so damned good in 16-17, it was really hard to watch him struggle so badly this year.