That's purely for defensive reasons late in the third. Boudreau did it in the Kings game also. When the game is tight he moves to Ryan - Bonino - Selanne as that line is more reliable in their own end.
That wouldn't bother me, but Palmieri wasn't on 2nd line at all. It was Beleskey-Ryan-Selanne. Which was stupid. They want to play a more defensive lineup later in the game fine, but taking him off that line the whole game was asinine.