It’s the Phillies’ worst-case scenario, a nightmare they prefer not to think about, much less actually ever confront as a reality.

Imagine if J.T. Realmuto, crouching behind home plate, takes a foul tip off his bare hand, or his wrist. The All-Star catcher breaks a bone and has to miss at least four weeks, maybe six or eight. Andrew Knapp goes from a seldom-used backup to the primary catcher, Deivy Grullon from a prospect with nine career big-league at-bats to a backup role.

End scene. Roll credits. Season over. Thanks for playing.

It could happen at any time, in any season. Such is the nature of being a catcher. It’s what makes Realmuto’s durability -- 116, 124, 125, 111, and 130 starts behind the plate per season since 2015 -- so impressive and his contract status -- he’s eligible for free agency after the season -- such a hot-button issue.

But all players, not just catchers, are more vulnerable this season. A three-week ramp-up to a 60-game sprint figures to heighten the risk of muscle strains, ligament sprains, and other injuries that could linger for most of a season that is 67% shorter than normal.

If that isn’t enough, players must dodge the COVID-19 pandemic while working, traveling, and, in some cases, living among one another. It isn’t just getting infected, either. Getting exposed to someone who has the virus could put a player out of commission for at least a week.

Teams are already dealing with absences. A scan of the National League East shows that Atlanta Braves first baseman Freddie Freeman (sick with COVID-19) and pitcher Cole Hamels (left triceps tendinitis), New York Mets ace Jacob deGrom (back tightness), and Washington Nationals outfielder Juan Soto (exposure to someone who tested positive for COVID-19) have missed all or most of training camp.

There’s a reason teams were allowed to bring as many as 60 players to camp. They’re going to need most of them. That’s the reality of pandemic baseball.

At the risk, then, of sounding too much like Debbie Downer, it’s worth wondering which player the Phillies can least afford to do without in a condensed season in which losing streaks will be magnified and slow starts insurmountable.

Most indispensable Phillies player? Aaron Nola would be in consideration for that title.
JOSE F. MORENO / Staff Photographer
Most indispensable Phillies player? Aaron Nola would be in consideration for that title.

Bryce Harper is the Phillies’ biggest star and highest-paid player, and not having his left-handed power in the middle of the order would be damaging. But they do have outfield depth. Jay Bruce, for instance, could go to left field and Andrew McCutchen could slide over to right. It wouldn’t be ideal, but it might cushion the blow.

The Phillies learned last year about life without McCutchen, and it wasn't any fun. They had a 33-26 record when the leadoff man tore a ligament in his left knee and went 48-55 the rest of the way without him. McCutchen's on-base percentage was .378; the Phillies' replacement leadoff hitters reached base at a .298 clip.

But manager Joe Girardi has noted center fielder Adam Haseley’s potential on-base skills, which might improve in his second big-league season. Roman Quinn has the speed to bat atop the order if he’s able to stay healthy, always a necessary caveat for him.

Like most No. 1 starters across baseball, Aaron Nola is indispensable. He’s also one of only five pitchers to work at least 200 innings and rack up 200 or more strikeouts in each of the last two seasons. The others: Justin Verlander, deGrom, Gerrit Cole, and Patrick Corbin. Subtract any of them from their team’s rotation and it would be a haymaker, if not a knockout punch.

The Phillies exhaled, then, when Nola missed only three days of training camp after testing negative for COVID-19 but having been exposed to an infected person. It appears he even will be ready to make his third consecutive opening-day start.

But the Phillies upgraded the starting rotation by throwing $118 million at free-agent right-hander Zack Wheeler in the offseason. Wheeler has No. 1 starter-quality stuff and would put the team in a slightly better position to withstand Nola’s missing a start or two.

There isn't any replacing Realmuto, though.

J.T. Realmuto finished 14th in the NL MVP voting last season and would have fared better if the Phillies hadn't fallen out of the wild-card race.
JOSE F. MORENO / Staff Photographer
J.T. Realmuto finished 14th in the NL MVP voting last season and would have fared better if the Phillies hadn't fallen out of the wild-card race.

Part of it is the position. The Phillies don’t have nearly as much depth behind the plate as, say, on the infield, where Scott Kingery, Didi Gregorius, and Jean Segura can all play shortstop, and top prospect Alec Bohm is waiting in the wings at third base.

But Realmuto is also the best catcher in baseball. He was worth 5.7 FanGraphs WAR last season, tied for seventh in the National League, and finished 14th in the NL MVP voting. If the Phillies hadn’t faded in the wild-card race in September, Realmuto would have garnered even more MVP support.

Realmuto also rarely comes out of the lineup. While some teams divide the catching position more evenly (the Nationals, for instance, had Yan Gomes and Kurt Suzuki catch 787 and 628⅓ innings, respectively, last season) Knapp was on the roster every day and got a grand total of 160 plate appearances. He didn’t start back-to-back games until Sept. 23-24, when Realmuto was dealing with a knee injury.

In a season of 60 games, it's conceivable that Realmuto could start almost all of them.

"I don't see why I can't start every game, maybe not necessarily catching," Realmuto said recently. "I could easily see myself catching 50 to 55 games. I don't know if Joe will let me do that or not, but I feel like with the DH being in play and also being able to slide into first base, if it was up to me, I'd play all 60 games."

“Next man up” might be the mantra in pandemic baseball. But that principle barely exists for the Phillies at the catcher spot, and they’d rather not live through the nightmare of experiencing it.