Boston Celtics guard Jaylen Brown (center) drives to the basket against Philadelphia 76ers forward Dario Saric (right) and guard Ben Simmons (left) during the first half in Game 5 of the second round of the 2018 NBA playoffs at the TD Garden.

From a statistical view, the playoff debut of Philadelphia 76ers point guard Ben Simmons was a success. Simmons averaged 16.3 points, 9.3 rebounds and 7.7 assists in 10 games, while in the first round against Miami becoming the first rookie to record a triple-double in the playoffs since Magic Johnson did it with the Los Angeles Lakers in 1980.

The Sixers, in reaching the playoffs for the first time since 2012, were a better team this season with the addition of Simmons.

But also from a statistical view, the second round of the playoffs for Simmons was a nightmare. In the five-game series, the 76ers had a plus/minus of minus-63 when the guard was on the court, compared with a plus-48 when he was on the bench. It was the worst plus/minus of any player in the series.

Ben Simmons had the worst +/- of any player in the Celtics/Sixers series. pic.twitter.com/LcTI5ppyNq — SportsCenter (@SportsCenter) May 10, 2018

The Sixers, in getting eliminated by the Boston Celtics in five games, were a better team in the series when Simmons was watching from the bench.

Clearly, the Sixers were an improved team with Simmons, just like the Utah Jazz are a better team with Donovan Mitchell even though he had a plus/minus rating of minus-42 as his team was eliminated by the Houston Rockets in five games.

But a close look at a stretch of the fourth quarter reveals plays where Simmons’ plus/minus numbers can be easily explained.

• 6:55 remaining. Game’s tied at 94 and Simmons is in a place where he is usually most dangerous, leading the break. Simmons dribbles past four defenders but never gets squared and throws up a wild shot attempt (which leads to an Al Horford layup the other way and a 96-94 Celtics lead).

• 6:16 remaining. Simmons responds with another drive to the basket where he’s met in the lane by Horford. The result: another wild miss (and a Horford basket on the other end, increasing Boston’s lead to 98-94).

• 5:02 remaining. The Sixers are on defense and down four when Simmons bites on a Horford pump fake. When Horford attacks, Dario Saric has to leave Jayson Tatum to help. Horford feeds Tatum for a dunk and a 102-96 Boston lead.

• 1:32 remaining. The Sixers lead by four when Horford sets a screen on Simmons, who’s unable to fight through, which gives Tatum space to attack. The Sixers are forced to rotate, allowing Horford to dive the lane for an alley-oop dunk.

Simmons is not the sole reason that Philadelphia came up short in the series.

Joel Embiid checked into the game with just under nine minutes left and launched three jumpers — a 3-pointer, a top-of-the-key jumper and a fadeaway 12-footer — in a span of 68 seconds. He missed badly on all of them and missed a potential game-tying shot in the closing seconds (although his 27 points, 12 rebounds and four blocks did help keep the Sixers in the game).

“We didn’t play our best,” Embiid told reporters after the game. “We came in here and made a lot of mistakes.”

T.J. McConnell, who provided inspired play with starts in the last two games, missed a wide-open 10-footer in the lane with 2:25 left that would have increased the Sixers’ lead to five.

And J.J. Redick missed a wide-open three with 1:11 left that also could have given Philadelphia a five-point lead.

But the spotlight, with the glaring plus/minus numbers, falls on Simmons, who ended the regular season as the apparent Rookie of the Year.

That was the regular season. Simmons wasn’t even the best rookie in the Eastern Conference semifinal series (Tatum finished Game 5 with 25 points and scored 20-plus in seven straight playoff games) and played a secondary role in the playoffs to the player likely to be his closest competitor in the Rookie of the Year voting, Mitchell.

It’s shocking that Simmons, having spent two years in an NBA environment (he sat out his first year with the Sixers), has not developed his shooting. Against the Celtics, Simmons shot 60.5 percent in the restricted area but just 26.7 percent between 5 and 9 feet from the basket.

He has no outside game (he didn’t make a 3-pointer all season) and no midrange game. So the Celtics rotated their frontline players to defend the Sixers point guard, which allowed players such as Horford and Marcus Morris to help defenders because they could sag in the lane and didn’t have to go under screens, as Simmons was never a threat to pull up and shoot from deep.

“I’m just learning,” Simmons said after the game. “This is just a start for me. I have a long way to go.”

The first order of business: Learn how to shoot.

He should be in the gym today if he wants to avoid a career where he’s annually subjected to memes like this:

IT’S OVER DONE HANG THE BANNER BEN SIMMONS DID NOT A MAKE A THREE POINTER THE ENTIRE 2017-2018 SEASON. pic.twitter.com/APJm9uMg23 — Has Ben Simmons Made A Three Yet? (@hasbensimmons) May 10, 2018