Casey Janssen stretches during workouts at Space Coast Stadium in February. He is back in D.C., and will pitch for Potomac on rehab assignment Thursday. Reinhold Matay-USA TODAY Sports

Casey Janssen walked into the Nationals clubhouse Wednesday for the first time since opening day, and he caught up on the bullpen goings-on. He shook hands with Tanner Roark and congratulated him on his save. He shook hands with Sammy Solis, and congratulated him on being there. Janssen entered spring training as the Nationals’ presumptive set-up man, so he was a welcome sight for his teammates, who have navigated injuries and growing pains without him.

Janssen battled rotator cuff tendinitis late in spring training, and has been rehabbing the injury in Viera since. He worked through a throwing program and pitched in simulated games there. He will head to Class A Potomac to pitch an inning Thursday, his first rehab assignment. If all goes well, he will get a few days off, then try to pitch innings on back-to-back days, according to Nationals Manager Matt Williams. At that point, the Nationals will assess his status.

Janssen said his shoulder feels “a lot better than when I went down” to Florida, but that his stuff is “not major-league ready, which is annoying for me.

“It’s good to compete, good to get out there and face hitters and stuff like that. But still need my velocity to pick up a couple ticks and just get things a little bit more sharp with the breaking stuff,” Janssen said. “But come up here, get a few more outings in and see where I’m at.”

Tendinitis can be tricky, as it is not something to be fixed, but rather calmed down in the hopes that it will not return. Janssen said he thinks it is gone, but of course can’t be sure.

” I do think it was one of the those things that once you got past a certain stage in it, I think it just becomes something you’ve done your whole life. By no means do I need to be 100-percent pain-free everywhere,” Janssen said. “We’ve learned to pitch with a little bit of something. But at that point in spring training, I knew it was something that would be tough to get through for a season.”

Janssen said he does not require a “whole heck of a lot of innings” before being ready for a typical season, so he does not anticipate needing that many before returning to the Nationals. But he does need to feel like he is pitching near full strength.

“I think if my velocity’s back and my command’s what it should be, and I’m spinning the ball right, I think it can come quick,” Janssen said. “Obviously everyone’s going to talk and figure it out, but I guess I don’t need a whole heck of a lot of games as long as my control and command and velocity are there.”

>>>>> Veteran reliever Jose Valverde,  the right-hander the Nationals signed to a minor league deal last week, reported to Class AAA Syracuse on Wednesday. Valverde has been throwing in Viera for nearly two weeks, building up arm strength.

“He’s throwing the ball good. He’s throwing the ball like he has in the past, mid-90s fastball,” Williams said. “He’s been a wonderful teammate to everybody down there. He’s taking care of the kids, and now he’s getting a chance to further the progression and see if he can help us. He was very interested in coming and being a part of it if possible, so that’s kind of where we’re at. He’s going to keep throwing.”