Storen, who is expected to return shortly after the All-Star break as he recovers from April surgery to remove bone chips from his right elbow, threw only eight pitches in his outing on Thursday.
"Even the first outing, I'm sure he's a little sore from that," Johnson said. "He'll be kind of monitored day by day. Hopefully he'll throw more than eight pitches and get a good workout [at Potomac]. If not, I told him and [pitching coach Steve McCatty] that rather than him going to the bullpen and start throwing, I want to see him in game situations."
With Tyler Clippard 13-for-13 in save opportunities since taking over the closer role on May 22, Storen's role upon his return remains up in the air. Johnson has said the team needs to see how Storen responds a day after "airing it out" and throwing all his pitches.
"It's not going to be imperative for back to backs, with the type of bullpen I have," Johnson said. "It's all about arm endurance and how it bounces back. The first time he comes back here and pitches, I wouldn't back to back him. I wouldn't close him."