The Sixers have a week to get ready for the playoffs. These are the five things they need to be working on.

Nick Nurse said late Saturday that the 76ers’ coaching staff is already compiling “in-depth notes” on potential playoff opponents. And that they can officially add that night’s loss to the Detroit Pistons to the mix.

The final week of the regular season has arrived, with the Sixers (43-35) still chasing their peak as a team — along with their seeding.

They were overmatched against the East-leading Pistons, playing without Joel Embiid and on the second night of a back-to-back. During this home stretch, the Sixers’ obvious first goal is to win as many of their four remaining games as possible, starting with a challenging visit to the red-hot San Antonio Spurs on Monday.

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Yet within those matchups, there are some areas the Sixers must sharpen in order to elevate out of the play-in tournament — Saturday’s loss bumped them back down to seventh place in the standings — and compete with the contenders they would face in the first round.

The Sixers have finally gotten a handful of games with their core during the past week or so, when Tyrese Maxey, Joel Embiid, and Paul George all returned from weekslong injuries or suspension. They will now take every minute possible on the floor together, to build timing and chemistry while identifying the best personnel groupings and substitution patterns.

The primary rotation wrinkle still in flux is whether to start (and/or close with) Dominick Barlow or Kelly Oubre Jr. as the forward alongside George. Barlow has excelled while playing off Embiid as a cutter and doer of the unsung things. Oubre provides more of a scoring punch and was inserted back into the first group with Embiid sidelined Saturday.

“Both are great at their role,” George said. “… Either one could [start or close], and we would still thrive.”

Nurse has also continued to tinker with when to use reserve centers Andre Drummond or Adem Bona, with Drummond starting Saturday in Embiid’s absence against Detroit All-Star Jalen Duren. Quentin Grimes, who went scoreless on 0-of-4 shooting Saturday, still needs a decent dose of shots. And Justin Edwards, Trendon Watford, and Cameron Payne are among those who have slipped out of the rotation.

Nurse hopes the Sixers will have their full roster available for three of the four remaining games. The exception is their final back-to-back against the tanking Indiana Pacers, when Embiid (and possibly George) is unlikely to play.

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The Sixers allowed another 16 offensive rebounds against the Pistons, the latest evidence of what’s been a season-long issue. The Sixers entered Sunday ranked 20th in the NBA in defensive rebounding (31.6 per game), and 25th in second-chance points allowed (16 per game).

That could be a significant statistical mismatch in the postseason. Potential first-round opponents: Detroit, Boston, and New York — plus consider Charlotte in that possible play-in matchup — all entered Sunday ranked in the league’s top seven in offensive rebounding.

“Those rebounds, it kills you,” rookie VJ Edgecombe said. “Especially when you just guarded, say, for 23 seconds. Now you’ve got to guard again for [another] 14.

“That should be our main focus. … I feel like, when we finish possessions, we will be pretty good.”

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The Sixers, somehow, surrendered 71 first-half points against two opponents in the past four days. The first was the Pistons, who made 61.4% of their attempts before intermission because the Sixers “did a really, really poor job of handling their cutting,” Nurse said.

The other was … the tanking Washington Wizards.

Tightening that end of the floor — the Sixers entered Sunday ranked 17th in defensive efficiency this season, allowing 114.9 points per 100 possessions — has been a popular topic with Nurse and players throughout the past week.

After Monday’s loss at the Miami Heat, Embiid implored the Sixers to stop “overhelping” and instead keep ball handlers in front of them. During that inexcusable first half in Washington, Nurse said the Sixers were not guarding the ball closely enough. Friday’s marquee win against the Minnesota Timberwolves, when the opponent shot 37.6% from the floor, looked like a positive step.

But against Detroit, Maxey said the Pistons used the Sixers’ aggressiveness against them and that they got “overzealous.” The point guard added that transition defense — the Sixers entered Sunday ranked 27th in fastbreak points allowed (17 per game) — remains an area of improvement.

An asset on that end of the floor down the stretch should be George, who has become a defensive “quarterback” for the Sixers.

“That’s really where my mind is coming down the stretch,” George said.

Though the Sixers feel like a veteran playoff team — Embiid, Maxey, and George have all enjoyed fabulous performances throughout their careers — key members of this season’s rotation have not yet experienced this level of basketball.

The intensity of recent games in Charlotte and Miami, plus this home back-to-back against Minnesota and Detroit, provided an initial glimpse of what the postseason is like. Bona mentioned that teammates have informed him about the physicality uptick, and that fouls are typically called less often. Edgecombe whipped out the cliché that every possession matters.

The next two environments in San Antonio and Houston should also help prepare the young Sixers for what’s to come.

“I’m ready,” Edgecombe said. “But you’ve got to experience it, you know?”

This is always the caveat with this team, huh?

Saturday provided another reminder. Embiid had a scheduled absence on the second night of a back-to-back to manage the oblique injury that kept him sidelined for a month. And Maxey spent time during the game shaking his right hand and breathing deeply.

“I definitely hit it,” Maxey acknowledged. “But I’ll be all right.”

A positive health development? George played both games of a back-to-back for the first time this season, and continued to look physically sharp while totaling 20 points, five rebounds, four assists, and two steals against Detroit.

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