SAN DIEGO – The Nationals placed Keibert Ruiz on the 10-day injured list this evening with a head contusion, the result of an errant foul ball that struck the catcher on the right side of his head as he watched Friday night’s game from the dugout.

Drew Millas was recalled from Triple-A Rochester to take Ruiz’s roster spot and will back up Riley Adams, who takes over the team’s No. 1 catcher for now.

Ruiz was standing next to Adams during the top of the fourth Friday night at Petco Park when teammate Josh Bell scorched a foul ball toward them from close range. The ball whizzed past everyone but ricocheted off the back wall of the dugout and struck Ruiz on the head. He immediately retreated to the clubhouse alongside director of athletic training Paul Lessard and was taken to an area hospital for a CT scan.

That scan showed no evidence of a concussion or any fractures, but Ruiz has a lump on the side of his head and has complained of headaches and dizziness since the incident, prompting the team to place him on the 10-day IL rather than the 7-day concussion IL (which requires an official concussion diagnosis).

“I don’t feel 100 percent, and I don’t feel good enough to catch today,” Ruiz said. “If I get another foul ball in my head, I don’t think that would be good. I have two kids that need me. I’ve got to take care of my health.”

Ruiz will remain with the team through the rest of the road trip, which ends Sunday in Anaheim. He’ll be closely monitored by the club’s medical staff, which planned to have him try riding an exercise bike today to see how he responded to that level of activity.

As a catcher, Ruiz is used to taking foul balls off various parts of his body, but he said this was the first time he’d ever been hit directly on his head, making it an unnerving feeling.

“It’s really different,” he said. “Obviously, I don’t have the helmet on, and it hit me straight on the head. I’ve never had this feeling before. It’s different.”

Adams, who turns 29 on Thursday, had already been getting increased playing time in the last week, a reflection of Ruiz’s struggles at the plate. He clubbed his third homer of the season Friday night in Los Angeles, snapping an 0-for-32 slump in the process.

Manager Davey Martinez said Adams will likely get the bulk of the starts now behind the plate, with Millas the clear backup.

“(Millas) has been catching really well, and as of late he’s been swinging the bat a lot better,” Martinez said. “We’ll get him up here, get him some playing time. But for the time being, Riley gets an opportunity to play quite a bit.”

Millas, 26, has 31 games of big league experience from the last two seasons but is making his first appearance on the major league roster this year. His season at Triple-A Rochester was off to a rough start, but he picked it up recently and posted a .789 OPS over his last 17 games.

Millas got word of Ruiz’s injury around 11:30 p.m. Monday. He quickly rushed to Innovative Field in Rochester to gather his belongings, slept for a few hours and went to the airport for a 5:30 a.m. flight to JFK Airport in New York, then a long connecting flight to San Diego. He walked into Petco Park around 3:30 p.m. local time, three hours before first pitch.

“I mean, that’s a freak incident, and you don’t wish it on anybody, obviously,” he said of the circumstances surrounding his promotion. “And it gave me an opportunity, but not one that … I don’t want to say I’m not happy about it, because I’m happy to be here. But it’s unfortunate how it happened, how it all played out.”