The incident occurred Friday night, and a penalty wasn't called on the ice.
"With the puck bouncing in Carlo's skates as he attempts to locate it, Wilson approaches from outside his field of vision and delivers a high, hard hit that makes direct contact with Carlo's head, driving him violently into the glass and causing an injury," the league explained.
"Through no fault of his own, he's (Carlo) in a position where he is unable to brace for contact, anticipate the hit, or protect himself in any way from Wilson, who was approaching from outside of his field of vision ... While there are aspects of this hit that may skirt the line between suspendable and not suspendable, it is the totality of the circumstances that cause this play to merit supplemental discipline."
Wilson has now been suspended five times in his career. Before being disciplined Saturday, his most recent ban came in 2018 when he was given 20 games for a high hit on St. Louis Blues forward Oskar Sundqvist.
The Capitals' enforcer will forfeit $311,781.61 in salary for his current suspension, according to Sportsnet's Chris Johnston.
Boston used the controversial hit as a rallying point in Friday's 5-1 win. Defenseman Jarred Tinordi fought Wilson in the second period, and the Bruins buried three goals with Wilson in the box.
Carlo was taken to the hospital after the hit but has since been released.