The Boston Celtics have had some clear issues of late with passing and player movement and the general cohesiveness that had them near the top of the league.

There has been too much of the individualistic, “I’ll take the ball and go make a play now,” and too little of the cutting that either rewards that player with a shot or moves the defense and opens the floor for a teammate.

Brad Stevens and Danny Ainge have both called the Celts out for not playing hard enough, though they were better in that regard in Thursday’s loss to the 76ers in Philadelphia. But that quality is more than just running fast or diving on the floor for a loose ball. It’s also being mentally strong enough to stick with basic elements of the schemes at both ends of the floor.

In all these regards, perhaps the most difficult thing to judge right now is how much of a factor the Celts’ current schedule plays into all this.

Clearly there is no real practice time, no solid chance for a hearty session of remedial roundball.

The Celtics’ first three-game losing streak of the season was reached on the second night of a back-to-back and in the fifth game in seven days.

And if you’re looking for a light at the end of the tunnel, it’s actually shining down on the C’s from the rafters of an NBA arena.

They host New Orleans, Chicago and Detroit on Saturday, Monday and Wednesday, then play Thursday in Milwaukee against the East-leading Bucks. That will bring the run to nine games in 14 days.

After that? They’ll simply play every other night until the All-Star break in mid-February.

These are the kind of scheduling matters that afflict each team. This just happens to be the Celtics’ turn in the meat grinder.

“It’s tough,” Marcus Smart told the Herald. “I mean, the schedule has been tough for us, but we can’t use that as an excuse.

“I know it’s a cliché. You hear it all the time, but it’s the truth. This is what we signed up for, and we’ve got to go out there and be determined and show our resiliency. You’ve got to want it. And the good teams, when it’s tough, they get even better, and that’s what we’ve got to do.”

Said Gordon Hayward, “Yeah, I mean, it certainly is a tough grind for us here. It’s tough. It’s the NBA. There’s not much else to say.”

The slippage in the Celtics’ game is evident.

“With fatigue, you miss things that you probably wouldn’t miss,” said Smart. “You don’t see openings that you should. Or you see it, but you’re late. You’ve just got to get better. You’ve got to do whatever you can do to make sure that doesn’t happen — or at least limit those times.”

Added Hayward, “It certainly makes things more difficult. Your legs aren’t as fresh as they probably could be, and mentally, too, you’re a little tired and fatigued. But that’s all part of it, so it’s hard to make excuses on that end.

“We’ve got to go out there and play our hardest. You know, sometimes you come up short.”

SIXERS 109, CELTICS 98

Thursday night

BOSTON (98)

Hayward 4-11 0-0 8, Tatum 4-13 6-6 15, J.Brown 2-12 0-0 6, Walker 10-20 1-1 26, Theis 4-6 0-0 9, Smart 9-14 1-1 24, Ojeleye 0-2 0-0 0, Kanter 4-7 0-0 8, G.Williams 1-3 0-0 2. Totals 38-88 8-8 98.

PHILADELPHIA (109)

B.Simmons 9-15 1-4 19, T.Harris 7-17 0-0 16, Richardson 9-16 10-10 29, Horford 7-11 1-3 17, Scott 3-8 0-0 7, Thybulle 0-4 0-0 0, Ennis III 2-5 0-0 6, Korkmaz 3-6 0-0 9, Pelle 3-3 0-0 6, Burke 0-3 0-0 0. Totals 43-88 12-17 109.

Boston 35 20 25 18 — 98

Philadelphia 26 22 29 32 — 109

3-Point Goals—Boston 14-36 (Smart 5-7, Walker 5-11, J.Brown 2-4, Theis 1-3, Tatum 1-5, G.Williams 0-1, Ojeleye 0-2, Hayward 0-3), Philadelphia 11-27 (Korkmaz 3-5, Ennis III 2-3, Horford 2-3, T.Harris 2-5, Scott 1-3, Richardson 1-5, Burke 0-1, Thybulle 0-2). Fouled Out—None. Rebounds—Boston 43 (Kanter 11), Philadelphia 57 (B.Simmons 9). Assists—Boston 17 (Tatum 4), Philadelphia 24 (Richardson 7). Total Fouls—Boston 16 (Smart 4), Philadelphia 11 (Pelle, Richardson, Horford 2). A—20,822.