WASHINGTON -- The Pirates were encouraged by early observations of closer Jason Grilli's right forearm injury. But they are not yet able to breathe a sigh of relief.
Grilli was diagnosed with a right forearm strain and was placed on the 15-day disabled list Tuesday. He is back in Pittsburgh, where team doctors will perform a battery of tests to figure out what caused Grilli's right forearm to tighten up in his 24-pitch outing Monday.
"The initial read is encouraging," general manager Neal Huntington said. "But until we have the [complete] read, it doesn't make sense for us to get out in front and speculate on what it is and how long he's going to be down."
Grilli, 36, did not have an MRI before leaving for Pittsburgh. Huntington said the Pirates hope to have a complete diagnosis on Grilli in the next three days.
A forearm strain is a vague diagnosis teams give when there is incomplete information. Sometimes, it is as simple as a muscle strain. Other times, it can be as severe as a torn ligament that requires Tommy John surgery.
"There's a lot in the forearm, so it's kind of a generic diagnosis," Huntington said.
Grilli was optimistic Tuesday, Huntington and manager Clint Hurdle said.
"Jason got to see a number of the teammates before he left, and I think that was good for everybody," Hurdle said. "I told him we'll leave the light on for him."
The Pirates will turn to Mark Melancon to close games in Grilli's absence. And Hurdle plans to use a combination of pitchers -- Tony Watson, Bryan Morris, Justin Wilson and Vin Mazzaro -- to fill Melancon's spot as the setup man. The Pirates recalled reliever Vic Black from Class AAA Indianapolis to take Grilli's spot on the 25-man roster.
Huntington said the Pirates will monitor the trade market as well.
While the Pirates will notice a change from Grilli's fun-loving attitude in the bullpen and intense focus on the mound, Hurdle said he believes his team will adjust just fine as long as the wins and saves keep coming.
Injuries are nothing new to Grilli, a former first-round draft pick who missed two full seasons while battling different injuries -- Tommy John surgery sidelined him in 2002, and a catastrophic quad injury kept him off the field in 2010.
"He has a faith that's real," Hurdle said. "He said this is going to come good. This is just another chapter in the deal. And he'll just work his way through it."
Grilli was upbeat, though disappointed, in talking with his manager Monday night and Tuesday morning.
"As we talked [Tuesday] morning, he said, 'You know, I just wanted to stay on the wave,' " Hurdle said.
"And I said, 'What's really cool is nowadays, you big-time surfers, you've got that little thing around your ankle that you strap to the board. So when you do fall off the wave, you don't lose your board. We'll just paddle back out and get you on another wave.' "