MacDonald left the game with an injury in the middle of the second period after blocking a shot (and taking a holding penalty to boot). Instead of going to the box, he went to the locker room while Keith Aucoin served his penalty.
(It was tough to tell on the replay, but it looked like the holding happened, or at least became more noticeable, as MacDonald winced and fell on his check after the shot arrived.)
Anyway, the Islanders, in the parlance of our times, reported quickly that he would not return due to an "upper body" injury. After the game Arthur Staple of Newsday had bad news: His sources said MacDonald has a broken hand.
Though the Islanders survived multiple lead changes and won the game after MacDonald's departure, his injury would be a serious loss. He partners with Travis Hamonic to check the opposition's best players, of which the Penguins have quite the menu.
However, though it's a hit to the defensive work, it might be an opportunity for Thomas Hickey, who has been scratched since Game 1. Hickey is a good possession player and partner to Lubomir Visnovsky, but not a likely candidate to partner with Hamonic.
It's the first key injury the Islanders have suffered this year, which is a little fortunate after 52 games (and a welcome change to their injury luck in recent seasons).
Now begins the reflection on how they'll adjust. The big question is probably who partners with Hamonic now? Captain Mark Streit has spent time with Hamoinic in the past. Hamonic is a righty, so the Isles have ample lefty complements to mix in, and Radek Martinek is a righthanded shot if they wanted to really mix up the pairs.