The Phillies spent the offseason rebuilding their core. They’re about to learn if they have enough depth. | Scott Lauber

Andrew McCutchen made it through nine consecutive major-league seasons without ever missing more than 16 games, a run of extreme durability that was testament to being “built Ford-tough,” in his words, and also lucky as heck.

Play any sport long enough, especially at the highest possible level, and you’re bound to twist the wrong way or lose your footing on wet turf or incur some other freak accident. It happens all the time, and the fact that it didn’t happen to McCutchen until the first inning on Monday night in San Diego was a minor miracle.

It’s also the reason that teams never stop looking to strengthen their rosters. Injuries are unavoidable, so depth is paramount. The more talent a general manager can stockpile means the less scrambling he will need to do when attrition takes its inevitable toll. Just ask the New York Yankees. Or the Houston Astros.

The Phillies’ depth was already being tested in the bullpen, where a half-dozen relievers are on the injured list. Seranthony Dominguez, who left Wednesday’s game in the eighth inning complaining of elbow pain, could become the seventh, pending the outcome of an MRI.

But now they’re shorthanded in the outfield, too. McCutchen tore the anterior cruciate ligament in his left knee and will need surgery. His season is over after 59 games, his streak of good fortune snapped in a misstep during a rundown, all of it occurring seven days after Major League Baseball placed Phillies center fielder Odubel Herrera on administrative leave after his arrest on assault charges stemming from an alleged altercation with his 20-year-old girlfriend in an Atlantic City casino on Memorial Day.

Imagine losing two-thirds of your opening-day outfield in a week. The Yankees can. Giancarlo Stanton and Aaron Judge went down with injuries 20 days apart at a time Aaron Hicks was still dealing with an injury suffered in spring training. But they turned to Brett Gardner and Clint Frazier and called up Mike Tauchman and signed Cameron Maybin. They mixed and matched and got by with what they had, and, somewhat incredibly, they’re in first place in the American League East.

A similar story is unfolding in Houston. George Springer, Carlos Correa, and Jose Altuve are on the injured list, yet the Astros haven’t missed a beat, comfortably leading the AL West because of contributions from players such as Jake Marisnick, Derek Fisher, and Aledmys Diaz, before he also got hurt.

The Phillies, who have spent 43 consecutive days atop the National League East, must now do the same in an outfield that still includes Bryce Harper. But, do they have enough in reserve to make up for all they have lost? Or will general manager Matt Klentak need to add “outfield depth” to his pre-trade-deadline shopping list?

Klentak spent most of the offseason star-hunting to remake the roster. The Phillies signed Harper, McCutchen, and reliever David Robertson via free agency and traded for shortstop Jean Segura and all-star catcher J.T. Realmuto. All were brought in to join homegrown slugger Rhys Hoskins and ace Aaron Nola in forming the team’s rebuilt core.

Building up the roster’s depth was understandably secondary to those splashy moves. Hoskins spoke Tuesday of the Phillies’ need for a “next-man up mentality," but it’s unfair to ask top outfield prospect Adam Haseley to replace McCutchen. Instead, it will fall squarely on the shoulders of some of those stars.

The Phillies raced to the division lead despite Harper’s May slump and Nola’s bloated earned-run average. If Harper continues to heat up at the plate and Nola gets on a roll every five days, it would go a long way toward carrying the Phillies through this adversity.

But Klentak also felt compelled last weekend to trade for Jay Bruce, a veteran left-handed hitter who could add power to the bench. That move looks even timelier now that Bruce is taking over for McCutchen in left field. Haseley got called up Tuesday, and though 23-year-old center fielder went 0-for-4 in his major-league debut, he knocked in the winning run the next day. Scott Kingery can play the outfield, although he’s expected to get more playing time at third base in place of struggling Maikel Franco.

Utility infielder Sean Rodriguez will see time in the outfield, too. Nick Williams is stashed in triple A, and oft-injured Roman Quinn might begin a rehab assignment soon.

The Phillies will let those options play out before deciding whether Klentak needs to go searching for others.

“Every time you have a disappointing [personnel] loss, you also have an opportunity to improve and an opportunity to meet a bar and step up to the challenge,” manager Gabe Kapler said. “And I think the guys in our clubhouse are prepared for the challenge.”

Let there be no doubt that the Phillies are facing a challenge. They’re about to learn whether their rebuilt roster can withstand it.