Mark Zuckerman of MASN noted the Nats' announcement confirmed it was a debridement and microfracture procedure. He's expected to rehab "throughout the offseason."
Murphy parlayed his memorable 2015 playoff run with the New York Mets into a monster debut year with the Nats. He set new career highs in batting average (.347), home runs (25) and runs batted in (104) and earned his second All-Star Game selection in 2016.
He remained a vital cog throughout 2017 with a .322/.384/.543 slash line and 23 homers.
The 32-year-old infielder has stayed mostly durable in recent years. He's played at least 130 games in every season dating back to 2012. He did spend some time out of the lineup late in the 2016 season because of a strained left buttocks, though. More recently, he was sidelined with neck and hamstring issues.
Looking ahead, it's unclear at this stage whether the Nationals expect Murphy back at full strength in time for 2018 Spring Training. He's suddenly become one of the most impactful players in baseball and the team can't expect more than replacement-level numbers at the position if he ends up missing time next year.