Soriano blew a three-run lead in the ninth inning of Friday's 9-8 loss. He has a 6.98 ERA in 21 appearances since the All-Star break, and he had a 0.97 ERA in 37 appearances before it. He has blown seven save opportunities in 38 chances this season, including five after the break, and has given up at least one run in seven of his last 12 outings.
"His fastball velocity is good, the command isn't quite where he wants it, certainly," Williams said about Soriano. "The slider, the depth of his breaking pitch, is not there right now."
How long Soriano is out of the closer's role, if he returns to it at all, depends on how quickly he can get the flaws in his delivery worked out, Williams said.
"We have to figure out why he's missing location with the fastball, why his slider depth is not what he wants," Williams said. "For the next couple of days we'll let him ease his mind a little, work on it, do some video and get back to where he has been."
The 34-year-old, who is a 13-year veteran of the Mariners, Braves, Rays, Yankees and Nats is 4-1 with a 3.04 ERA and 31 saves this season.
"There's nobody in particular we're going to announce as the closer in the next few days," Williams said. "The good thing is we've got guys with experience doing it, and anybody can. We'll see how the game unfolds."
Washington (79-60) enters play on Saturday with a seven-game lead over the Braves in the NL East and the best record in the National League.
- Chris Mascaro