Ramos had an MRI on the hamstring Wednesday and it revealed a Grade 1 strain, according to manager Matt Williams.
"It's going to be a few days at least," Williams said. "If it were a couple of days, it may be fine. A doctor looked at it, studied it and thought a week to 10 days anyway. So we made sure it's taken care of and he is back in 15 days. The thing we don't want is he gets out there and plays and it gets worse and you are looking at 30 days."
It marked the second time Ramos has been placed on the disabled list this season. The first time came a day after Opening Day when he broke his left hamate bone.
On Wednesday, Ramos was upbeat and "normal," but he understood why he was placed on the DL. He realizes the Nationals need to have a healthy catcher in case something happens to Jose Lobaton, who was in Thursday's starting lineup.
"They put me on the DL because they need to have somebody 100 percent in case Loby gets hurt or something like that. They need to get somebody ready," Ramos said. "I want to work. I want to keep working. Let's see how I feel the next couple of days."
Ramos is in great shape, but Lobaton suggested to Ramos that he needs to start a new program in order to keep his legs healthy. Ramos agrees with his teammate. Ramos had hamstring issues last year and missed half the season. The hamstring injuries have been caused by running the bases.
"I need to do something different," Ramos said. "I need to work more on my hammy. I need to work on my hammy because I don't have any problem with any part of my body, just my hammy. I need to work 100 percent with my hammy."
As for Leon, this is his second stint with the Nationals this season. He is having a productive year with Triple-A Syracuse, hitting .294 with six RBIs.
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the Time. He also can be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.