Imagine you’re a professional basketball player in the NBA, but every season the game of basketball would change. The court gets a bit wider, the ball bounces a little less and the league says each team must now use one fewer player. Suddenly the game plays differently, and that turnaround jumper doesn’t feel quite like it did a few months ago.

That’s how it feels to compete in Call of Duty League (CDL), the competitive esports circuit for one of the world’s most popular video games. Every year, the franchise’s publisher, Activision Blizzard, releases a new Call of Duty game, so — every time the Earth completes one orbit around the sun — the first-person shooter has new weapons, tweaked mechanics and other variations on machines of war. Simply put, the pros are learning a new game every season.

Chris “Simp” Lehr, a professional CDL player with two world championships, said the ever-changing landscape of Call of Duty is just what you sign up for when you compete in the 12-team league.

“Personally, I think it’s refreshing,” Lehr said. “It’s a whole new game, a whole new experience.”

However, Lehr and other pros indicated there is one aspect of new games that they focus on intensely: maps.

This offseason, the CDL is preparing to compete on “Call of Duty: Vanguard,” a series entry set amid some of the key conflicts of World War II that’s scheduled to release on Nov. 5. But players and coaches in the professional league aren’t worried about reverting back to antiquated guns like the MP 40 or BAR. Three CDL players and one assistant coach told The Post that it will be the map layouts that dictate competitive play next season.

“Maps go such a long way,” said Ricky Stacy, an assistant coach for the Los Angeles Guerrillas. “That’s what makes map construction so challenging for developers."

Earlier this month, Sledgehammer Games, the developer behind “Call of Duty: Vanguard,” launched an open beta showcasing four multiplayer maps. So far, professional players say Eagle’s Nest, named after Adolf Hitler’s mountain retreat, and Hotel Royal, set in the heart of Paris, show promise. But none of them had positive things to say about Red Star, an open map centered around a snowy Soviet plaza and inspired by the Battle of Stalingrad. Stacy said Red Star is a map built for casual players, but it’s “too big and too campy” for competitive matches in league.

“It’s just really, really big,” Lehr said, referring to Red Star. “I don’t know how anyone would get anything done.”

“Vanguard” will launch with 16 standard multiplayer maps — twice as many as last year’s installment in the franchise, “Call of Duty: Black Ops Cold War.” Anthony “Shotzzy” Cuevas-Castro, a player for the Dallas Empire, told The Post that the news is “music to our ears.” Competitive Call of Duty players devote hundreds, if not thousands, of hours playing 4v4 matches on a certain subset of maps from a game. Players often talk about “competitively viable” maps, referring to structured, often smaller environments that allow for tactical gameplay rather than the massive, freewheeling maps built for the casual Call of Duty fans to enjoy.

“We kind of have to hope for the best for us because there’s not really a lot of competitive maps guaranteed,” Lehr said.

CDL players are often looking for smaller maps with roughly three lanes — left, middle and right — toward the opposing team that connect through close-quarters environments. The challenge here is that Activision Blizzard often prioritizes entertaining its casual fan base over the competitive integrity of league matches.

The emphasis on the general audience is a product of basic economics. There are thousands of casual fans for every player trying to go pro. Activision Blizzard earns billions of dollars from updating Call of Duty every year, while revenue from the esports league is believed to be a small fraction of that. A Call of Duty fan who gets the latest game over the holidays can play matches with up to 48 other players in any number of formats. Altogether, it’s a much different experience than what CDL players face in competitions.

CDL players say maps that are fun for the casual fans don’t necessarily translate well to the league. Casual maps are built for big fights — a.k.a. “Team Deathmatch” mode — where players throw themselves at each other in pursuit of the most kills. League players want smaller maps, and they also want less chance for pure luck to decide the outcome of a gunfight. Symmetrical, three-lane maps are easier to assess. Players can predict the opposition’s movements based on where they were last seen and where the map’s spawn points are. Lanes provide a basic flow to the match. An open field, for example, is just feeding ground for good snipers.

Meanwhile, other multiplayer first-person shooters like “Valorant” or “Counter-Strike: Global Offensive” were created around the competitive structure of the game; every map, every item and every game mode is designed with tournaments in mind.

“ ‘Valorant’ is built for competitive,” Lehr said. “But with us, the way the CDL plays out is not the same at all as casual [public servers].”

“Call of Duty: Vanguard” will be introducing a new game mode, Patrol, which requires players to occupy and defend a moving objective that floats across the map. When Activision first announced Patrol, the CDL teased that it could become a part of the competitive circuit. But Lehr said he’s not sure Patrol will be a mainstay for the league; it’ll depend, again, on the maps available.

“As long as good maps come out, Patrol could be viable,” Lehr said.

Castle and Dome, two maps from “Call of Duty: World at War,” which first released in 2008, will also be rereleased for “Vanguard.” It’s not clear whether those two are competitively viable, according to the pros. Stacy said the maps that were fun “when you’re 13” don’t always translate well to league play.

CDL players do seem optimistic about what they’ve seen so far in the beta. Mechanically, players say the game feels like a return to 2019′s “Modern Warfare.” Dylan “Envoy” Hannon, who now plays for the Los Angeles Thieves, said the beta felt “super smooth.” From what they’ve seen so far, the game looks promising.

“From playing ‘Vanguard’ already, I have high hopes for this season,” Hannon said. “I see a lot of hope in it so far, and I just can’t wait to see the whole game at launch.”

The start date for the league’s third season has not yet been announced. The last two seasons have started in late January and early February.

There are also bound to be changes to the game now that the beta is over. On Thursday, Sledgehammer wrote in a statement on their website that they’re working on “nerfing the sun” and “removing dognados” from the game. (Yes, here’s a link to a dognado.)

“As a reminder, Beta was just a sample of the overall ‘Call of Duty: Vanguard experience,’ ” Sledgehammer wrote. “You can expect more maps, modes, and weapons in 'Vanguard’ on November 5.”

Read more from The Post:

5 big changes coming to Call of Duty with ‘Vanguard’ you can experience in the beta

The untold origin of Verdansk, the Gulag and ‘Call of Duty: Warzone’

After esports org taunts opponents with plane banner, players ground rivalry talk