Dalpe's skills at least seemed to mesh with the other guys on that line, which is why I'm having such a hard time figuring out the thought process.
There could be a few things.
1) Maybe they want that line to be a bit more defensively responsible. They haven't been great in their own zone so if they aren't scoring, then Muller may want them to be better defensively as well. Having both Dalpe and Skinner on that line makes it difficult to put Jordan out against other teams top lines.
2) Maybe as I said, they want Dalpe to go down, score a few goals, work on his game a bit and get some confidence back and they'll call him back up shortly. Remember they did that with Faulk last year when he struggled.
3) Maybe after seeing how the Canes reacted against physical teams like Boston and Philly, he wants to try and mix things up a bit. Dalpe CAN be sent down without clearing waivers, so he's really the only choice in this case.
Anyhow, IMO, the Canes have much bigger fish to fry than Dalpe and that winger spot. I don't see a problem with this move and will wait to see how things play out over the coming weeks before over-reacting to it.
EDIT: Looks like Joe beat me to it with a lot of the same points.