Of the three, Ness actually has the most NHL experience to date: 29 games including 20 this season, 25 for Matt Donovan (including 22 this season before his demotion), and 16 for Calvin de Haan, all but one of them coming this year.
However by size and by pedigree, Ness probably has the longest odds of the three to have a long NHL career. De Haan has long been most highly rated though injuries delayed his arrival.
Donovan was first in the pecking order over the summer and in training camp, though some mistakes landed him back in Bridgeport. And Ness was recalled when Donovan was returned to the AHL, but de Haan has carried the heavier load and responsibility ever since his recall.
Anyway, Ness has been on the ice for a few notable goals against in recent games (much like Donovan before his demotion), so you wonder if those stand out in the club's decision-making.
On the other hand, the move leaves the Islanders at six healthy defensemen, though a three-game homestand means any imminent recall (Donovan?) is easily executed, weather permitting. Donovan has three goals, 11 assists in his last 17 games since being returned to the minors.