LOS ANGELES — Dodgers right-hander Yoshinobu Yamamoto was placed on the 15-day injured list before Sunday’s game against the Kansas City Royals with tightness in the triceps of his pitching arm.

Manager Dave Roberts said Yamamoto, 25, would undergo testing Sunday to determine the severity of the injury and a recovery timeline.

“He’s a guy that we’re still trying to learn a lot about, and appreciate the fact that the most important time of the season is yet to come,” Roberts said. “His health is paramount. So for us to be proactive and put him on the IL seems like the smartest thing.”

Yamamoto, playing his first year in the majors after departing his native Japan and signing a record $325 million, 12-year contract, is 6-2 with a 2.92 ERA.

Yamamoto left Saturday’s loss to Kansas City after two innings. He said through an interpreter after the game that his scheduled start the previous Thursday against Texas had been pushed back because of the tightness.

He also said the tightness was gone for most of Saturday, but he started feeling it again when he was warming up before the game.

Yamamoto threw two-hit ball over seven innings at the New York Yankees on June 7. He tossed 106 pitches, the fourth straight time he had thrown more than 100.

Roberts said he has been mindful of Yamamoto’s pitch count, but also noted Yamamoto was used to throwing 120 pitches or more when he pitched in Japan.

With Bobby Miller returning to the rotation for Wednesday’s game at Colorado, the Dodgers will still have a five-man starting staff. Clayton Kershaw will also make his first rehab start this week.

Los Angeles’ rotation went into Sunday’s game with the majors’ seventh-lowest ERA at 3.49.

The Dodgers also placed right-hander Michael Grove on the IL with a right intercostal strain. Right-handers J.P. Feyereisen and Michael Petersen were called up from Triple-A Oklahoma City. To make room for Petersen on the 40-man roster, right-hander Joe Kelly was transferred to the 60-day IL.

HOUSTON — Ronel Blanco had the second hitless outing of his brief major league career but was pulled after seven innings as the Houston Astros beat the Detroit Tigers 4-1 on Sunday.

Manager Joe Espada shared part of the conversation he had with Blanco when he removed the dominant right-hander from the game.

“I just told him how proud I am of what he’s doing,” Espada said. “This is a guy that came out of nowhere and he continues to perform at a high level. He has really picked his team up through injuries and he goes out there and he does things we need him to do.”

Blanco (7-2), who threw the only no-hitter in the majors this season April 1 against Toronto, was just as good this time in the 20th start and 37th appearance of his career. The 30-year-old threw 94 pitches with 65 strikes and tied a season best with eight strikeouts. He walked three.

“I was just attacking the strike zone,” he said through an interpreter.

Ryan Pressly replaced Blanco to start the eighth and gave up the Tigers’ first hit, a two-out single by Wenceel Perez.

Jose Altuve hit a three-run homer for Houston.

Blanco is the second pitcher in franchise history to have two starts with at least seven hitless innings in the same season, joining Framber Valdez, who did it last year.

The Tigers couldn’t do much of anything against Blanco a day after they had a season-high 19 hits in a 13-5 trouncing of the Astros.

Blanco didn’t allow a baserunner until he walked Gio Urshela with two outs in the fifth.

He then walked Akil Baddoo and Carson Kelly to load the bases, but retired Zach McKinstry on a flyout.

Espada said it wasn’t a difficult decision to replace Blanco because of how many pitches he has thrown this year, noting that he has had four outings with more than 100 pitches and two with 98.

“But did I want him to be more efficient earlier and give him a shot? One hundred percent,” Espada said.

Blanco said he wasn’t upset when Espada took him out.

“I threw a lot of pitches and I wasn’t going to be able to finish it,” he said. “So, I just accepted it.”

Blanco made a good defensive play for the second out of the sixth when he grabbed a comebacker hit by Matt Vierling. He then sat down Riley Greene on a popup.

Urshela reached with two outs in the seventh on a throwing error by third baseman Alex Bregman. Blanco then retired Baddoo on a fly ball that center fielder Jake Meyers caught on the warning track.

“We did battle,” Tigers manager A.J. Hinch said. “We obviously couldn’t get anything started against him. The three walks, you have a chance with two outs, but he wiggles out of it. And then he just continued to hit spots and threw a lot of different pitches.”

After the hit by Pérez, Pressly sat down Vierling before Josh Hader took over for the ninth. Mark Canha singled with one out and scored on a double by pinch hitter Andy Ibanez.

Urshela grounded out and Hader struck out pinch hitter Jake Rogers to end it.

Detroit starter Kenta Maeda (2-3) permitted five hits and four runs in five innings.

Altuve hit a leadoff single before moving to second on a wild pitch with one out. The Astros took a 1-0 lead when he scored on a single by Yordan Alvarez.

Mauricio Dubon singled with one out in the second and Chas McCormick drew a two-out walk. Altuve made it 4-0 with his shot to center field.

LOS ANGELES — Dodgers shortstop Mookie Betts suffered a fracture in his left hand when he was hit by a 97.9 mph fastball from Dan Altavilla during the seventh inning of Sunday’s game against the Kansas City Royals.

The fracture, which is to a bone in Betts’ left wrist, will not require surgery, according to manager Dave Roberts. There is no timetable for his return, though he is expected to be out “for some time.”

“It’s a big blow. I feel bad for Mookie because he’s having an MVP-type season,” Roberts said.

The pitch hit Betts at the top of the hand, near the wrist. Betts fell to the ground and was writhing in extreme pain in the batter’s box as trainers and Roberts came out to tend to him.

Those watching on television and in the lower deck at Dodger Stadium could clearly hear the ball making contact with Betts’ hand.

Betts went 0-for-3 before exiting Sunday to drop his batting average to .304, ninth in the majors. He was fourth in on-base percentage (.405) and tied for fifth in hits (86).

Betts was asked what’s next for him.

“I’m honestly not sure,” he said. “Obviously, I’ll be watching the boys and cheering them on. Other than that, just kind of rest, maybe use it as a mental break and be ready to go whenever it heals up.”

Miguel Rojas is expected to see the majority of time at shortstop, according to Roberts.

The Dodgers, who defeated the Royals 3-0, head to Colorado for a three-game series starting Monday.

The Associated Press contributed to this report.