I think it should look like

Moore-Matthews-marner
Johnsson-nylander-kapanen
Timashov-kerfoot-mikheyev

i like that line up alot, reunite johnsson and kappy

I think in this case less is likely more. Give Spezza time with Marner and whoever on the other wing and keep the other lines largely intact.

I would like to keep the Matthews line together but I can’t see spezza replacing Tavares. My idea here is just moving Matthews into Tavares spot and nylander to Centre. It looks like there is more going on but it really isn’t.

With Tavares out of the lineup we will see if Marner truly is the player some people think he is.

I have felt that Marner is a very good player but also benefited from playing with Tavares. Regardless of lines, it's time for Marner to show he can step up while his linemate is out.

my only problem with that is as good as Spezza is he wont be able to keep up with the others so i feel he would be better if kerfoot was injured.

Its time Babs really unleashed Matthews. Let him go toe to toe with the best and he's been at his best when he's had Nylander on his wing. I know Spezza can't step in for Tavares without there being a drop off but with Kerfoot doing what he does on the 3rd line you can run Matthews and him against the best the other team has to offer and then give Marner, Spezza and whoever some softer opposition against 3rd liners. Really get them moving.

What? Kerfoot isn't injured and obviously no one really replaces JT. That being said with Kerfoot and Matthews the other two centres, why change all 4 lines when you can insert Spezza and keep everything that has been working, working still and just weather the storm with JT out. Give the hard matchup to Matthews or Kerfoot and give Spezza soft 3rd line competition. Should really open things up for Marner as well.

I think Marner needs to play with Matthews. Just like all the other teams the 2 best players are on the same line. ex. McDavid/Drasaitl, Marchand/Bergeron, MacKinnon/Rantannen,Benn/Seguin and so on.
GIve it a real shot. IT's not like they are running away with the league on what they have been doing. Time for change!

So your idea would be

Johnsson-Matthews-Nylander
Mikeyev-kerfoot-kapanen
Moore-Spezza-Marner
Timashov-shore-Gauthier

That would work too but I don’t know if Babs will go for it.

Yeah something like that. I know some are going to say, that is an insult to Marner but I don't think Marner will be hurt by this. And if it doesn't work out then move Marner to the 2nd line with Kerfoot and Kap onto the Spezza line. I don't think Babs is going to change everything around. That often creates problems all over the lineup that don't need to be made.

Speeza will he slotting temporarily in Tavares spot.
Demoting that line to 3rd lines makes sense.