PITTSBURGH -- The Pittsburgh Pirates will have to see if they can keep their hot start going without Oneil Cruz. The 6-foot-7 shortstop had surgery late Sunday to repair a fractured left ankle and is out at least four months.

Cruz's left leg bent awkwardly underneath him as he tried to score from third on a chopper in the sixth inning of Sunday's 1-0 victory over the Chicago White Sox. Cruz opted to slide late and collided with the legs of White Sox catcher Seby Zavala, causing Cruz's leg to fold up underneath him as his momentum carried the rest of his body across the plate.

While the Pirates believe Cruz will be able to return by mid-August, manager Derek Shelton stressed he's more concerned about Cruz's health and state of mind. Shelton added that there was a "sense of relief" that the injury wasn't worse.

"My solace is in the fact that he's OK," Shelton said.

Pittsburgh placed the 24-year-old Cruz on the 10-day injured list and called up utility player Mark Mathias from Triple-A Indianapolis. Rodolfo Castro, who switched from second base to shortstop after Cruz was injured, started for the Pirates Monday when they began a three-game series against the World Series champion Houston Astros.

"I think in the early going (Castro) will get the majority (of the starts)," Shelton said. "We'll probably see (Ji-Hwan) Bae over there at some point, too, just depending on the matchup and moving guys around or just actual off-days."

Cruz, together with third baseman Ke'Bryan Hayes, 26, represents a left side of the infield that is a major piece of the Pirates' future, a group that excels in the field, though Hayes is still finding his way at the plate.

Pittsburgh has won five of six to get to 6-3, the club's best start since 2018, the last time the Pirates finished with a winning record. Cruz is part of the foundation the franchise is attempting to put in place under general manager Ben Cherington.

Cruz dazzled with his bat, his arm and his legs as a rookie in 2022 and started this season hitting .250 with a home run, four RBIs and three stolen bases. He also drew seven walks in nine games after earning just 28 walks in 87 games a year ago.

"(His absence) affects a lot, just the range that he has and the presence he has on the field, the guy he is, the leadoff hitter and how he runs the bases, all of that," Hayes said. "He impacts the game in a lot of different ways just by being on the field so it's definitely a big blow."

Pittsburgh believes it will be better able to cope with that blow thanks to an offseason influx of experienced players, including outfielder Andrew McCutchen and first baseman/designated hitter Carlos Santana.

"Nobody is ever going to have a team that doesn't suffer any type of setback," outfielder Bryan Reynolds said. "It's all going to come down to how we respond to it. We have a good veteran group. We've got young guys that are focused, too. ... I think we'll be able to handle it."

The Associated Press contributed to this report.