Nationals’ series opener at White Sox postponed by rain

CHICAGO — Monday night’s game between the Washington Nationals and Chicago White Sox has been postponed by rain.

It will be made up as a straight doubleheader on Tuesday.

Each team pushed its pitching rotation back one day.

Washington’s Trevor Williams will face fellow right-hander Chris Flexen in the opener of the doubleheader. Williams is looking for his third consecutive win, and Flexen is 2-0 with a 1.69 ERA in his last three starts.

Nationals left-hander Mitchell Parker and White Sox right-hander Erick Fedde take the mound in the second game. Fedde began his major league career with Washington and is facing his former club for the first time.

Chicago won three of four against Cleveland in its previous series. The White Sox are 9-7 since they dropped 22 of their first 25 games this season.

Washington has split its last six games. It dropped two of three at Boston over the weekend.

TRAINER’S ROOM

Nationals: RHP Josiah Gray (right elbow/forearm flexor strain) was slated to throw a bullpen session Monday. … OF Lane Thomas (sprained left MCL) is hitting in the cage, throwing and running on grass. Manager Dave Martinez said Thomas could begin running the bases in the next couple of days. … OF Jesse Winker felt a little better a day after he left Sunday’s loss to the Red Sox because of back spasms. Before the series opener was postponed, Martinez said Winker might be available as a pinch hitter late in the game. … RHP Cade Cavalli (elbow surgery) is scheduled to throw a simulated game on Tuesday. He had a short bullpen session on Saturday. … 1B/DH Joey Gallo (left shoulder sprain) is scheduled for another rehab appearance with Triple-A Rochester on Tuesday.

White Sox: CF Luis Robert Jr. (right hip flexor strain) is going to try running at 90 percent, and — depending on how that goes — play in some rehab games in Arizona this week. “The next couple days, the next three or four days, is going to be critical for what happens at the end of the week coming up,” manager Pedro Grifol said. … INF Yoán Moncada (left adductor strain) was slated to begin hitting left-handed on Monday. The switch hitter has been batting from the right side, along with taking ground balls and doing some drills. ”He’s a little further behind Robert, but he’s also coming along good,” Grifol said. … INF Danny Mendick (lower back tightness) is joining Triple-A Charlotte to begin a rehab assignment. … Grifol said he doesn’t think RHP Dominic Leone (back tightness) is going to need a rehab stint in the minors.