(Brian Garfinkel/GETTY IMAGES)

Nationals Manager Davey Johnson said Rodriguez didn’t report any discomfort after throwing his first bullpen session last week. The reliever threw again on Tuesday afternoon in front of pitching coach Steve McCatty. If he doesn’t feel any pain after this one, Rodriguez could begin a rehab assignment, Johnson said.

Rodriguez had been dealing with a balky back and the Nationals placed him on the disabled list to clear a roster spot for Jayson Werth when he returned on August 2. The fireballing right-hander with mind-boggling stuff was dealing with another string of uneven command and his 5.83 ERA was highest among Nationals relievers. He already missed 24 games earlier this season with a jammed index finger.

The Nationals placed DeRosa on the disabled list on August 8, freeing up a roster spot for then-backup middle infielder Cesar Izturis. Johnson has said DeRosa might need some minor league rehab at-bats before returning DeRosa also missed 50 games earlier this season with an oblique injury. He is hitting .152 in 66 at-bats, but is valued for his veteran presence and postseason experience.

If both are ready, they could rejoin the Nationals in September.

More from The Washington Post

Boswell: Getting used to playoff baseball

Tuesday’s lineups

Implications of a wild win

Nats outlast Braves in 13 innings