Sean Doolittle isn’t coming off the disabled list anytime soon. (John McDonnell/The Washington Post)

Sean Doolittle joked that his fragile ego has been incapable of sustaining the ridicule that accompanies missing significant time with a silly toe injury, but the pain was real. As silly as it sounded, he couldn’t drive off the mound to pitch like that all-star closer he’s become. The discomfort was profound.

That toe injury eventually became a neuroma — doctor talk for pinched nerve — in his left foot, between his big toe and its neighbor. An initial MRI exam revealed nothing more. No structural damage. He thought his absence would be short. After a few days off, he tried it ramping it up. But he wasn’t recovering as expected so he underwent a second MRI Saturday morning, which revealed the problem all along: a stress reaction. Doolittle said his timetable for return will be measured in “weeks,” not “months,” but he figures to miss a chunk of time in addition to the 10 games he’s already missed since his last outing July 6. It’s another crushing blow for the reeling Nationals.

“At this point in this season, with everything going on, to not be able to help, it’s a really frustrating feeling,” said Doolittle, whose foot was back in a boot Sunday. “I want to be there for my guys. I feel like I’m placing a burden on the bullpen by not being with them. And the challenge is going to be kind of harnessing that energy and throwing it into whatever rehab I can do to do everything I can to be back as soon as possible.”

The Nationals will proceed with Kelvin Herrera, who was acquired last month, assuming the bulk of the save opportunities, with Ryan Madson and Brandon Kintzler filling in on occasion to close games.

“This was the reason why we went out and got Herrera,” Nationals Manager Dave Martinez said. “With Herrera, Madson, Kintzler, we’ll be fine. We’re going to miss him, but we have qualified guys down there that can close.

The stress reaction diagnosis wasn’t made initially, the 31-year-old Doolittle explained, because tests don’t show stress reactions immediately. They appear over time, as they worsen. If the discovery hadn’t been made and Doolittle continued attempting to work his way back, applying pressure on the problem area, then a stress fracture would have resulted. His season could have been over.

He believes the problem, which he described as a deep bone bruise, stems from the burden he places on that area in his foot with his delivery. He said he’s dealt with minor pain in the foot in previous spring trainings, but it’d dissipate with some time in the cold tub. This, for some reason, became a far more significant problem. He speculated it could have been aggravated when he hit the deck to avoid a comebacker July 5. He even re-watched the video again Saturday. He still wasn’t sure.

“I have a little more peace of mind now because we saw something on the MRI,” Doolittle said. “It was much more conclusive than the first one was so my brain’s like, ‘Alright, now we know what it is. We have a better idea of how to treat it. Where to go from here.’ So it kind of puts my mind at ease in that sense.”

Doolittle was encouraged with his progress for a few days. He threw off flat ground at 90 feet during the all-star break, which didn’t include an All-Star Game appearance because of the injury. He ran on it — first at 50 percent body weight on an antigravity treadmill then at full body weight. He even got on a mound to throw a bullpen on Friday. But Doolittle bluntly said the session didn’t go well. He called it “erratic.” He couldn’t drive off his left foot enough to give his fastball the life it usually carries. The pain wasn’t going away and something needed to change. He underwent the MRI the next morning.

“We really weren’t happy with how it was responding,” said Doolittle, who’s compiled a 1.45 ERA and 22 saves this season. “It was okay while I was throwing. It was definitely sore while I was throwing but it stayed really sore for a while afterwards, for several hours afterwards, so we decided to get an MRI.”

Doolittle said there isn’t a clear plan yet. How he proceeds depends on how he feels, which isn’t very predictable. He won’t throw for now but expects to soon. He can walk on the foot and bear weight on it, which will allow him to work in the weight room. But he doesn’t know when he’ll step on a mound again. He expects to some point this season. The Nationals need it to happen as soon as possible.