There is absolutely no reason for Detroit to do this. This trade makes Detroit older and costs an extra $1.25M in cap space.

Boychuck replaces Green, giving Cholowski a veteran partner. I don't think Seider will make the league next year (i could be proven wrong at the benefit of DET), but this shuffles a pretty bad contract in Nielson for someone of value. It's not like Detroit should care about cap right now anyway

No way we're signing Barzal, Pulock and Toews at those prices. Barzal's getting 10 most likely, Pulock 6-7 and Toews 5-6.

I think you dump Ladd on Detroit with Wilde or 1st as a sweetener. Boychuk is still serviceable and will be 6-7D next year then probably bought out final year of contract.
After that dumping Clutterbuck's and Komarov's contracts shouldn't be too hard.

"Detroit shouldn't care about the cap" says you have no idea about Detroit.

Detroit has 9 players on the roster and 13 RFAs and 9 UFAs with contracts that expire at the end of the season.
Mantha $7.5M
AA $6.8M
Bertuzzi $5M but could be higher if he continues to play like he is now.
That leaves about $16.2 to sign 11 more players. So I think Detroit should care about the cap.

Plus Detroit added Nemeth, Beiga and Hicketts is ready once Detroit gets rid of some dead weight. Detroit has Dekeyser, Hronek, Cholowski, Bowey, Nemeth, Biega and Hicketts thats 7 without adding any more dead weight like 35yr old dman who is making far more than he is worth. If Detroit makes any moves it will be to get rid of cap and try to sign Krug if he leaves Boston. I think you should take a longer look at the team you are making a trade with.

The Isles have no use for Frans. Man, you guys overrate the hell out of him.