The Colorado Rockies sent Opening Day starter Jon Gray down to the minors, optioning the right-hander to Triple-A Albuquerque.

Gray was 7-7 with a 5.77 ERA over 17 starts this season, but has particularly struggled since May 13 while posting a 7.25 ERA in his last nine outings. The Rockies replaced him on the roster Saturday with outfielder Raimel Tapia, who was batting .308 with 10 home runs and 48 RBI at Albuquerque.

Gray appeared to turn things around June 22, when he gave up one run over seven innings in a victory over the Miami Marlins, but followed that by giving up five runs and seven hits over four innings in a loss at San Francisco on Thursday.

At the start of play Saturday, Gray was fourth in the National League with 119 strikeouts.

Orioles pitcher done

Baltimore Orioles reliever Darren O’Day has opted for season-ending surgery to repair a left hamstring injury.

Manager Buck Showalter said the recovery time from the operation would be six months, compared to a 10- to 12-week absence if the right-hander attempted to rehabilitate the injury.

Showalter said surgery gives O’Day “a lot better chance of it not being an issue again. And that’s important.”

O’Day, 35, has struggled with injuries this season, missing a month with a hyperextended elbow before being sidelined for good after hurting his hamstring on June 26.

The side-armer is 0-2 with a 3.60 ERA in 20 games. He was placed on the 60-day disabled list on Friday.

Shin-Soo Choo sore

Shin-Soo Choo was out of the Texas Rangers lineup a night after reaching base in his 41st consecutive game.

Choo said before Saturday’s game against the Chicago White Sox that he has been dealing with a sore right quad for at least 10 days. He said it has really bothered him the last couple of days.

Manager Jeff Banister said it was a chance to get Choo off his legs with a day off. But the manager didn’t rule out him being a pinch-hitter.

Choo’s on-base streak is the longest for the Rangers since Otis Nixon’s 44-gamer in 1995, and five short of Julio Franco’s team record set in 1993. Choo matched Philadelphia’s Odubel Herrera for the longest in the majors this season.

Be careful out there

It’s expected to be sweltering Sunday at many ballparks, with temperatures likely to climb over 100 degrees in Texas for White Sox-Rangers, near triple digits in Baltimore, Philadelphia and Yankee Stadium, and into the mid-90s in Chicago and Cincinnati. On Saturday, three Twins left early with heat illness at Wrigley Field.

“Drink more water, try to stay by the fan. I try to keep a towel by my side and make sure I catch my breath,” White Sox shortstop Tim Anderson said. “It’s a mind thing. You can’t think too much about it. If you do, it’ll eat you up.”

Around the bases

The Toronto Blue Jays put right-hander Ryan Tepera (elbow) on the 10-day disabled list and recalled right-hander Jake Petricka from Triple-A Buffalo. ... The Cincinnati Reds sent minor-league catcher Joe Hudson from Triple-A Louisville to the Anaheim Angels for cash. ... The Tampa Bay Rays put right-hander Wilmer Font (lat strain) on the 10-day disabled list and recalled right-hander Hunter Wood from Triple-A Durham.