Ericsson is coming back very soon I guess. They could theoretically call Nyquist up I think until he gets off LTIR, but apparently they don't feel the need.
EDIT: But it's a moot point anyway since no one will claim Tootoo.
Nyquist has only two NHL games remaining before he loses his waiver exemption. Baring a meaningless one-game stint, he'll be with the team for the rest of the season if he's called up.