The 36-year-old righty retired LaMonte Wade Jr, the game's first batter, and then threw one pitch to Brandon Belt before Nationals manager Dave Martinez and athletic trainer Paul Lessard visited the mound.
Scherzer threw one practice pitch before heading back to the Washington dugout. He underwent an MRI, which revealed no strain.
Speaking after Washington's 1-0 loss, Scherzer said he tweaked the groin while warming up before the game.
"It could subside fairly quickly," Scherzer said. "Going into the clubhouse, I was frustrated as all to get out. Turns out a little grab was all it was.
"The good news is that it is not a muscle strain. I am really day-to-day. I am very confident this will be very mild.''
Nationals manager Dave Martinez said the team likely will have another update Saturday.
"We're still not out of the woods. We'll see how he feels tomorrow," Martinez said.
The three-time Cy Young Award winner entered the game with a 5-4 record and a 2.22 ERA. He began the night second in the National League with 104 strikeouts.
An injury to Scherzer could hold significant ramifications for the Nationals and next month's trade deadline. He is in the final year of a seven-year, $210 million contract and could be one of the game's biggest trade targets.
With a 25-34 record, the Nationals could make Scherzer available for trade if they fall further out of the playoff race.
Information from The Associated Press was used in this report.