SAN DIEGO -- The Nationals got a reliever back Thursday, but at the cost of another.
Washington activated right-hander Shawn Kelley from the disabled list before opening a four-game series against the Padres at Petco Park. To clear room on the roster, right-hander Ryan Madson, who hadn't pitched since Saturday, was placed on the 10-day disabled list with a right index finger sprain.
Kelley missed 51 games with a right trapezius strain. Before landing on the DL, he had four saves and a 7.00 ERA in 22 games. He pitched in eight games on his Triple-A rehab assignment, posting an 8.10 ERA.
"I knew I was going to have several outings, almost like a Spring Training, because it had been so long," Kelley said. "It was good, especially early, to know I didn't need to try to do too much the first couple outings, and I could just go out there and work on some things and make sure I felt good and then start to ramp it up toward the end of it."
During his rehab, Kelley had outings where he pitched in back-to-back games and entered mid-inning, tasks he'll be asked to do with the Nationals.
"I kind of did it all," Kelley said. "I even warmed up one time and then had to sit down."

Madson has not allowed a run since the Nationals acquired him from Oakland on July 16, striking out 13 over nine innings. He developed an issue with his right index finger that was first discovered during a doubleheader against the Giants on Sunday.
"He's doing OK," manager Dusty Baker said. "Turned out to be a little bit more than a blister. … These things happen. It just popped up. We don't know how or why or when or anything.
"We'll be whole here soon, hopefully."
Worth noting
• Baker said "right now" right-hander Stephen Strasburg is ready to start Saturday's game. Strasburg, a San Diego native, hasn't pitched since July 23 because of a right elbow nerve impingement. He is 10-3 with a 3.25 ERA this year.
• All-Star outfielder Bryce Harper, on the DL with a bone bruise in his left knee, made the trip to San Diego with the Nationals.
"He's not cleared to do much, but he's part of this team," Baker said.
• Right-hander Koda Glover, who had a 5.12 ERA in 23 games before going on the DL, tweeted Thursday that he had gotten a "great report" from a doctor as he works his way back from lower back stiffness.
"He's fishing every day," Baker said. "He's champing at the bit to come back and pitch."