Staal hasn’t actually been all that bad since the all star break.
Hes been horrendous.
Plays most of his minutes paired with DeAngelo but has still posted a negative xGF% since the ASB (Meanwhile, DeAngelo is heavily in the green there.) When games are tied or within a goal in either direction, hes the only defenseman who is in the red in xGF% since the ASB (Not counting Smith, since hes played 3 games there, but every other D is over 50%.)
Make no mistake about it, he is being carried by DeAngelo, who goes from being a good player when paired with Staal to excellent when away from him.