In a development that was at all times startling, familiar and somber, Giancarlo Stanton yet again reached the precipice of a return before suffering yet another setback that jeopardizes his season and perhaps career.

For a third time this season, the prodigious Yankees slugger attempted to run the bases and strained a calf.

The initial two strains, in April and June, occurred in his right leg. This week Stanton fell and sustained a strain in his left calf, manager Aaron Boone said Saturday.

Just like in June, Stanton had built up his calf carefully and reached the final stage of his progression — rounding the bases, which typically precedes a rehab assignment or immediate activation — before disaster struck.

Boone, who spoke with emotion in his voice, said Stanton’s strain is moderate, thus the designated hitter will continue to work toward a 2026 return.

Many players can make it back from such a graded strain within a month or two, but the 36-year-old Stanton, who has a long history of lower leg problems and is chiseled like few in the game, is not like many players.

His first calf strain, back on April 24 in Houston, was deemed “low grade,” according to the club, and he was sidelined until the second strain two months later.

Giancarlo Stanton of the New York Yankees on the dugout fence.New York Yankees’ Giancarlo Stanton is seen in the dugout as the New York Yankees play the Seattle Mariners on Thursday, August 13, 2026, at Yankee Stadium in the Bronx, NY. Robert Sabo for NY Post

There will be implications for the 2026 Yankees, who may have lost a key reinforcement (if one redundant with others on the roster) and arguably for the 2027 and beyond Yankees.

But Boone wanted to focus on the implications for a deeply respected, 17-year veteran who has the makings of a Hall of Fame case and zero World Series titles.

Giancarlo Stanton in a New York Yankees cap reacting on the dugout fence.New York Yankees’ Giancarlo Stanton reacts on the dugout fence on Aug. 13. Charles Wenzelberg / New York Post

“I admire him so much and who he is and the way he goes about things, and the same rings true for everyone in that [clubhouse],” Boone said before playing the Blue Jays in The Bronx. “They look up to him. They respect him. When he speaks, you listen.

“It means a lot to him to be able to go do this. And he understands who he is and what he means to the team when he’s in there. He has the utmost respect and admiration of everyone in that room, and especially me.”

Stanton was not expected to address reporters Saturday. The Yankees are obligated to pay $15 million of his salary next season, which is the final guaranteed year of a 13-year, $325 million pact originally signed with the Marlins.

Forty-four home runs shy of 500 and a ring missing from his résumé, Stanton has reason to continue to attempt to play, but there will be wonder whether his legs allow what they have not allowed this year.

“It’s been a tough road,” Boone said of Stanton’s season, which to this point consists of 24 March and April games. “Tough news. Just feel for G. because I know how bad he wants to be in there with us.”

Without Stanton, the Yankees would lose one proven, big-time October bat, though one who did not fit well within a group that is filled with DH types. Will Aaron Judge, who is again hitting as he recovers from a rib stress fracture, return to the outfield? The Yankees would prefer to use Ben Rice at designated hitter than at first base, where Luis García Jr. and Paul Goldschmidt could platoon in the postseason.

But such lineup questions were not front of mind Saturday.

“Obviously bummed for him,” Boone said of Stanton. “Been working his tail off every single day here trying to get this thing right.”