I don't see 13 better options that will push Grundstrom out.
We know the established group is set in stone, and that's composed of 10 names (Kopitar, Brown, Kovalchuk, Carter, Toffoli, A. Kempe, Iafallo, Clifford, Lewis, Wagner). Then you have two more spots and a healthy scratch spot or two to fill.
Who's going to push out Grundstrom? And who do you think the Kings need to protect from waivers?
That's 7 wingers. Maybe 8 if Carter moves over and Prokhorkin plays C. Even if Carter doesn't move, that probably pushes Prok to wing, which is still 8 wingers. Grundstrom's spot could come at the expense of Wagner, which nobody wants to see, but he doesn't have to clear waivers, and there are also 6/7 wingers other than him. He was up and down at the start of last year, then with Kovalchuk being out, and Lewis being out, and Pearson traded, and then Hagelin was out, Wagner got his chance in there somewhere.
There's never 100% health, but if we assume Wagner and Prokhorkin have spots to lose, I don't know where Grundstrom would go. Brown, Kovalchuk, Toffoli, Iafallo, Prokhorkin/Carter, Clifford, Lewis, Wagner. That's 4 lines worth of wingers. M.Kempe and/or Frk as place holders/healthy scratches. When some of those guys finally get dealt during the year, that'll change the equation. Grundstrom turns 22 in Dec. That's not quite the same as Petersen having to waste some time in the AHL at the age of 25 because they can't get rid of Quick. Grundstrom is less than 2 weeks older than Lizotte, and is younger than both Wagner and Luff, to put that in perspective. He's still a kid.
If nothing else, you can make the case for a number of young guys to get the chance, which is good.