Strasburg, who has been on the 10-day injured list since Aug. 15, has carpal tunnel syndrome in his pitching hand, as announced by Martinez on Friday.
Per MASN, Martinez said Strasburg was placed on the 60-day IL, meaning his 2020 season is over.
Strasburg got off to a rough start this season. In two starts, he was 0-1 with a 10.80 ERA and 1.80 WHIP. He also had just two strikeouts in five innings.
It was a far cry from the pitcher who was among the best in Major League Baseball for the first 10 years of his career.
The 32-year-old veteran is a three-time All-Star and has twice finished in the top five of National League Cy Young Award voting, including last season.
In 2019, Strasburg made 33 regular-season starts for the Nats and went 18-6 with a 3.32 ERA, 1.04 WHIP and 251 strikeouts in 209 innings. The win and strikeout totals marked career highs for the 2009 No. 1 overall draft pick.
Strasburg was also a superstar for the Nationals during their run to the World Series, as he went 5-0 with a 1.98 ERA and 47 strikeouts over 36.1 innings in six appearances. He was named World Series MVP in the Nats' seven-game win over the Houston Astros.
Though Washington lost its top offensive player during the offseason when third baseman Anthony Rendon signed with the Los Angeles Angels, there was still some hope it would contend behind the starting pitching trio of Strasburg, Max Scherzer and Patrick Corbin.
The Nats are tied for fourth in the NL East at 9-13, however, and making up ground will be difficult with one of the league's premier pitchers on the shelf.
Washington will continue to rely on Scherzer and Corbin with Strasburg out, but it will also need more from the rest of the rotation, which includes Anibal Sanchez, Austin Voth and Erick Fedde.