Hudson has a 4-1 record with a 2.59 ERA and 35 strikeouts in 23 games. He joined the Nationals in a midseason trade with the Toronto Blue Jays in 2019 and recorded the final three outs in Game 7 of the World Series a few months later.
The 34-year-old Hudson does have a history of injuries, including two Tommy John surgeries between 2012 and 2013 while with the Arizona Diamondbacks.
"We just figured it would be smart to shut it down for a couple days," Hudson said. "With my injury history, there was some cause for concern for me. I don't have any concerns long term. Hopefully it's just short term."
In his last appearance Wednesday, Hudson threw 31 pitches in 1⅔ innings in a win at Tampa Bay.
Manager Dave Martinez said Hudson had an MRI on Friday that showed only inflammation. The IL move is retroactive to Thursday.
The Nationals made a few other moves ahead of Saturday's doubleheader against the San Francisco Giants. Right-hander Erick Fedde was reinstated from the injured list and will start the first game. Fedde, who is 3-4 with a 4.35 ERA, last started May 16 at Arizona and was placed on the COVID-19 injured list May 19.
Right-hander Andres Machado was optioned and selected from Triple-A Rochester as the 27th man for the doubleheader. Machado made two appearances with the Kansas City Royals in 2017. The Nationals also selected the contract of Jefry Rodriguez from Triple-A Rochester, and Martinez said he could start the second game. Outfielder Yadiel Hernandez was optioned to Triple-A Rochester.
Right-handed reliever Will Harris (right hand inflammation) was transferred to the 60-day injured list. Harris was originally placed on the 10-day injured list May 23.