As a workhorse 20-year-old hockey player, it wasn’t much of a warning signal when Charlie McAvoy missed Monday’s Bruins practice with what the team initially called “a doctor’s appointment.” But it turned out to be a fairly serious absence as the Bruins announced later in the afternoon that their prized rookie is going to miss roughly two weeks after undergoing a procedure at Mass General Hospital to address an abnormal heart rhythm.

According to the Bruins statement: “After the Nov. 26 game, Charlie told team physicians that he experienced heart palpitations during the game. Subsequently he underwent an evaluation, which diagnosed him with a supraventricular tachycardia (SVT). The type of SVT Charlie has is not considered to be dangerous to his health but can recur at any time and causes significant symptoms.”