On Thursday, the NBA will announce the reserves for the All-Star teams as voted on by the coaches. Unlike the Western Conference, which has as many as 15 deserving candidates, the big question in the top-heavy East is whether the Celtics will get four spots.

Getting four All-Stars is a big deal. It’s happened only eight other times in NBA history and only twice since the Sixers pulled it off in 1983. Only the 1998 Lakers and 2006 Pistons have pulled it off in the last 27 years.

The Celtics have had three reps a staggering 31 times – and they have done it every season since Ray Allen and Kevin Garnett arrived – but they have had four All-Stars only three other times in franchise history: 1953, 1962 and 1975.

The argument against the Celtics getting four this season seems to focus on the rarity of the achievement. The question gets twisted into: Are the Celtics having a good enough season to warrant four selections, while other teams like the Magic and Bulls may be left with one? 

That’s really a non-existent issue. All-Star selections should be based on individual merit, and while team success shouldn’t be dismissed, this is about which players are having the best seasons.

The issue really isn’t if the Celtics deserve four All-Stars, but instead whether there are four Celtics having All-Star seasons.

Before we get into it, a brief review:

The starters as voted in by the fans are Derrick Rose, Dwyane Wade, LeBron James, Amar’e Stoudemire and Dwight Howard. The coaches select two guards, two forwards, a center and two wild cards.

That leaves seven spots with some room to maneuver in deserving players at crowded positions. Why the NBA insists on using traditional positions in a league where that matters less and less is a different matter.

The first three Celtics are easy selections.

Rajon Rondo leads the league in assists per game and has continued his development as coach Doc Rivers’ extended brain on the floor. He’s also one of the best rebounding guards in the league and a disruptive, albeit gambling, defender. There are simply no other point guards in the East in Rondo and Rose’s class. 

Garnett, meanwhile, has returned to his 2007-08 form and reclaimed his turf as a dominant defensive rebounder and defender. How good a rebounder has Garnett been? He ranks second behind Minnesota’s Kevin Love in terms of defensive rebounding percentage among power forwards.

His effort on the boards has been the essential difference between this Celtics team and last season’s. As an added bonus, Garnett scores 15 points and a game and shoots 53 percent, while locking down the opponent’s best big man on a nightly basis.

Paul Pierce is another no-brainer. He’s having one of his most efficient seasons as his shooting numbers are up and his turnovers are way down. Pierce is also rebounding better than he has in years and when Rondo missed seven straight games, he showed his versatility by taking over the ballhandling responsibilities and recording 47 assists.

That leaves Ray Allen.

The case for Allen is simple: At age 35, he may be having the best shooting season of his career. He’s shooting a career-best from the floor (51 percent) and behind the arc, where he’s making 46 percent of his 3-pointers. (In a weird twist, his 86 percent free throw shooting is his worst since his rookie season.) Perhaps even more impressively, he has played every game and is averaging 36 minutes a night.

While there’s no rule that says that the NBA has to take a two-guard, Allen’s competition for the other guard spot essentially comes down to Atlanta’s Joe Johnson.

Johnson is a very good player who does a lot of things well, and does them consistently. He averages more points, rebounds and assists per game that Allen does, but has he really had the better season?

The two things that stand out in Allen’s favor are his shooting percentages across the board and the fact that he has played nine more games, not an insignificant amount. But we can go a little deeper with the last two numbers.

Leaving Allen’s insanely good True Shooting percentage aside (which combines, 2’s, 3’s and free throws), focus on the Usage percentage (USG) of the two players.

Allen uses barely over 20 percent of the Celtics’ possessions when he is on the floor with a shot attempt, free throw or a turnover. Johnson, on the other hand, uses over 27 percent of Atlanta’s possessions.

This makes intuitive sense when you think about the two players. Allen is primarily a shooter in the Celtics offense, while the Hawks offense often runs through Johnson. 

While Allen’s primary role is shooting, he is a more important part of the Celtics offense than your average spot-up jump shooter who hangs out in the corner and waits for open looks out of double teams. Allen gets most of his shots on the move off screens, and his movement complements his teammates’ abilities perfectly.

Allen’s job is to force defenses to make choices. Should they switch or try to fight through screens? When opponents give him space he burns them, and when they focus too much attention on stopping him that opens up the floor for the other Celtics to make plays. Allen may not have the ball in his hands as much as Johnson, but in many ways the Celtics offense runs through his movement.

The argument for Allen comes down to a question of efficiency, the great buzzword of 2011. Allen is a far more efficient player because he uses fewer possessions to record comparable results. There are many more ways to slice this argument even thinner, but it all keeps coming back to the same thing: Ray Allen is having a better year than Joe Johnson.

That’s no knock on Johnson, who is a deserving candidate. But if it comes down to one or the other, as it does on this ballot, Allen is the choice.

Here are our All-Star reserve selections for the East:

Guards: Rondo, Allen

Forwards: Pierce, Garnett

Center: Al Horford

Wild Cards: Josh Smith, Chris Bosh

Toughest omissions: Johnson, Carlos Boozer, Andrew Bogut.