Ryan Mountcastle has a grin that masks his frustration and disappointment. It’s part of his calm demeanor, his warm and friendly personality.

He rode into the clubhouse this morning with his left leg propped on a scooter, an easier mode of transportation than the pair of crutches leaning inside his locker. His foot is covered by a heavy brace to begin the healing process after a freakish bone break.

Mountcastle lined a double into right-center field Saturday at Camden Yards and fractured the fourth metatarsal between first and second base. It caused him to stumble into the bag, with an awkward lunge that left him face-down in the dirt and in serious pain.

Talking about it for the first time this morning, Mountcastle smiled at members of the media who drifted toward him, chatted about his misfortune and naturally agreed to an interview request. He joked about his wife not liking the scooter, and he used the crutches for support while he stood.

With everything that’s gone wrong for Mountcastle health-wise, it’s amazing that he can stay so positive.

There was nothing unusual about running the bases or Mountcastle’s stride. For whatever reason, the bone couldn’t hold up under the pressure.

“No clue,” he said. “I touched first, and a step or two after that, just felt a pop in my foot and I sort of stumbled all the way to second there. Yeah, right when I got up I knew it didn’t feel very good.”

Mountcastle won’t need surgery, but he doesn’t have a timeline to return.

“Just sort of however long it takes for that bone to heal,” he said. “It could be a couple months. I don’t know.

“Just getting a bunch of treatment on it and taking some supplements to help with the bone healing and all that. That’s about it.”

This is Mountcastle’s first foot injury. He’s dealt with several others over the years, including the hamstring strain last summer that cost him more than two months. What he’s dealing with now is brand new.

“Just sort of felt it pop and didn’t feel great,” he said.

“I guess any time of year it’s not good, but it’s frustrating for sure. Put all that work in, especially offseason, spring training, all that. For something like this to happen is not fun. But just got to attack the rehab and get back soon.”

Adding to the bizarre nature of the injury is how Mountcastle wasn’t in the original lineup. Adley Rutschman was scratched with left ankle inflammation, forcing him onto the IL, and Mountcastle got a rare start.

His double in the second inning was clocked at 109.1 mph. He kept running, at least as much as he could.

“I took a good swing on it and I had a lot of momentum going toward second already, and it was either I was falling in the middle of the basepath or on second, so I just tried my best to get there,” he said.

If there’s any good news for Mountcastle, doctors confirmed that he didn’t suffer a Lisfranc injury, which is a fracture and displacement of the fourth metatarsal and requires a cast.

“So that was I guess the one positive that came out of this,” Mountcastle said. “Could have been worse.”

The Orioles have eight right-handed hitters in today’s lineup against their first left-handed opposing starter, Arizona’s Eduardo Rodríguez. A healthy Mountcastle would be at first base or serving as designated hitter. The Guardians are starting two lefties in the upcoming four-game series in Cleveland.

Mountcastle expressed confidence that he will return and that the team will be in contention, that it can withstand the early onslaught of injuries and he’ll have an impact in the stretch run.

“Like I said, I’m gonna attack the rehab and hopefully come back and try to help this team in the playoffs and beyond.”