For a team that sports a leprechaun as its mascot and a shamrock as part of its motif, the Celtics haven’t enjoyed great luck this season.

We’re not talking Len Bias or Reggie Lewis tragic levels of franchise-altering misfortune, or the conspicuous bad luck in the draft lottery dance of the ping-pong balls in 1997 or 2007. But it does feel like mystic NBA forces are conspiring against the Celtics’ master plan in a season gone sideways.

A surefire lottery pick headed the Celtics’ way suddenly isn’t a sure thing, and neither is Kyrie Irving reupping after this season. A certain mantle as the best team in the Eastern Conference isn’t so certain for a team that has done as much sniping off the court as on it.

Luckily, the Green enjoyed some good fortune Tuesday night in their feel-good win over the 76ers. Philadelphia’s Jimmy Butler, an 85.7 percent free-throw shooter, missed 3 of 6 free throws in the fourth quarter, including two of three when he could have tied the game with 74 seconds left. Much to the profane dismay of Sixers center Joel Embiid, the officials missed an obvious foul on Al Horford with Boston up 2 with 33.9 seconds left.

But a fun and fortuitous night in Philly without Irving and with the old Gordon Hayward doesn’t change the luck ledger this season. They say fortune favors the bold. Few NBA decision-makers are bolder than Danny Ainge, but his blueprint for redecorating the rafters has gotten smudged by unforeseen turns of fate.

A franchise that historically has enjoyed its share of good fortune has hit the luck equivalent of one of the dead spots in the old parquet floor. The ball has stopped bouncing their way.

Let’s count the ways that Lady Luck has jilted the Celtics:

■ At a season ticket-holder event on Oct. 4, Irving pledges that he wants to re-sign with the Celtics. By Feb. 1, he is telling folks to check back with him on July 1 about his desired NBA address for next season, saying that he doesn’t “owe anybody [expletive]’’ and that the Celtics are “still at the head of the race’’ — a race for his services no one knew existed.

Irving strained his right knee Saturday night against the Clippers trying to fight through a screen. The Celtics proceeded to blow a 28-point lead in their most ignominious defeat of the season, just one game after they blew an 18-point one to the Lakers and the guy Irving called for leadership lessons, LeBron James.

■ The 2019 Sacramento pick the Celtics own the rights to was supposed to be a top-five selection, with the understanding that it couldn’t be No. 1 overall because of a trade protection. Instead, the Kings have been the most surprising team in the league, starting Wednesday four games over .500 and possessors of the final playoff spot in the Western Conference.

Emboldened, the Kings added veterans Harrison Barnes and Alec Burks at the trade deadline to further decrease their odds of landing in the lottery. What once looked like a highly valuable asset for Ainge now looks like it’s not even going to be a lottery pick.

The Celtics picked up this selection by pulling off the basketball version of the Gardner Museum heist in the 2017 NBA Draft. Boston shipped the No. 1 overall pick to the 76ers, who used it on flop Markelle Fultz, in exchange for this pick and dropping down two spots to select Jayson Tatum. (Technically, the Celtics are entitled to the better of Sacramento’s selection or Philly’s pick in the 2019 draft, excluding the No. 1 overall pick.)

■ The Clippers owe the Celtics a lottery-protected first-rounder. The Celtics receive it if the Clippers make the playoffs this year or next. If they don’t, the pick reverts to a 2022 second-round pick. Doc Rivers and the Clippers were on track to deliver the pick this season before deciding to demolish their roster at the trade deadline to retool and retain their first-rounder. Now, their playoff potential is in doubt.

Making matters worse, as part of the tear-down, they traded their best player, Tobias Harris, to one of the Celtics’ chief competitors, the 76ers. So, the Clippers potentially robbed the Celtics of an asset while simultaneously making their road out of the East more arduous.

■ Celtics object of desire Anthony Davis is angling to join the Lakers. The good news for the Celtics was that Ainge swayed the Pelicans not to deal their trade-demanding superstar until after the season, when the Celtics would be eligible to take him on. But that’s a silver lining from an ominous cloud.

Davis and his agent, Rich Paul, a longtime member of LeBron’s claque, are plotting to have Davis join James in LA. Doubt has been cast about Davis’s willingness to sign long-term in Boston, with whispers from his camp that they’re concerned about Irving’s intentions.

Plus, Davis’s father declared that he doesn’t want his son to play for the Celtics. Anthony Davis Sr. lambasted the team as disloyal because of the way it dispatched Isaiah Thomas via trade.

His comments constituted bad luck and a bad look for Boston.

Oh, and New Orleans did the Celtics no favors by sending stretch four Nikola Mirotic to the Milwaukee Bucks.

■  The Celtics are owed a first-round pick from the Memphis Grizzlies from the Jeff Green trade in 2015, another instance of Ainge robbing a team. That pick is top-eight protected this year and top-six protected in 2020. It’s unprotected in 2021, when high school players might once again be eligible for the draft.

The Grizz took the tanking plunge when they shipped franchise fulcrum Marc Gasol out of town at the trade deadline. Unfortunately for the Celtics, they shipped him to the Toronto Raptors, bolstering another Boston rival.

The Celtics are unlikely to get Memphis’s pick this year. The specter of an unprotected pick in 2021 probably creates a more enticing trade chip for Ainge to dangle for Davis. Call me a parquet pessimist, but if Memphis hits on its lottery picks the next two years, they might not be as bad as anticipated when 2021 rolls around.

The great thing about luck is that it can change suddenly. Just ask the Patriots. One minute you’re on the wrong end of a catastrophe in Miami. The next you’re winning the overtime coin flip in the AFC Championship game in Kansas City.

The All-Star break could break the Celtics’ unlucky streak. We’ve been searching for their fortune fork in the road all season. Thus far, they have lacked communal spirit, killer instinct, and good fortune. Two of those they can control.

The Celtics need to leave as little to chance this year as possible, because luck has not been on their side.

Christopher L. Gasper is a Globe columnist. He can be reached at cgasper@globe.com. Follow him on Twitter @cgasper.