Chicago — Some of the Pistons’ struggles in the first part of the season can be attributed to poor defense and a disjointed offense.

The bigger issue is playing shorthanded, which has had a ripple effect on the roster. Not having Blake Griffin (hamstring/knee), Reggie Jackson (back tightness) and rookie Sekou Doumbouya (concussion protocol) has pushed Markieff Morris and Tim Frazier into the starting lineup — and to add some offensive muscle, Luke Kennard also was promoted.

Griffin and Doumbouya haven’t played in a game this season and Jackson played in just the first two before having increasing issues with his back, which have kept him out for the past week.

Griffin, who had minor knee surgery after last season, looks to be close to returning. He’s been ramping up his workouts and did some shooting reps in practices this week and at Friday’s shoot-around and pregame sessions.

The Pistons announced that Griffin would be re-examined in early November and although Griffin said he’s feeling better, there’s no clear timetable for his return.

“I feel great doing all this stuff out here right now. For me, it’s about trusting our (training) staff, these people who have literally dedicated their lives to putting us in the best possible position,” Griffin said. “Even if I feel great, I still have to listen to what they’re saying.

“I’ve completely stayed out because everybody on our training staff is unbelievable and they’ve put together a really good plan and they don’t really tell me anything beyond the next day.”

The Pistons miss Griffin’s presence on the offensive end, especially, but missing Jackson, who is one of their better 3-point shooters, compounds the problem. Frazier has been good in his starting role, but Jackson’s outside shooting presents another threat for defenses to monitor.

The back issues are a new injury for Jackson, who has had knee and thumb concerns in the past. The training staff is handling it with caution, to get him back to prime playing condition.

“He’s getting low-back tightness that is exacerbated with the activity. He can go a certain amount of distance and then it starts to flare up,” Pistons medical director Bernard Condevaux said. “Once it starts to spasm up, he’s not moving right.”

Jackson didn’t look to be 100 percent in the two games he played, averaging just 18 minutes and lumbering around the court in obvious discomfort. The plan is to try to get him back closer to full health before trying to play him again.

“We want to build him back up because he hasn’t been able to complete the last couple of games he’s played.” Condevaux said. “We want to make sure he’s in a position to play. He needs to play and move the way he needs to move.”

Doumbouya update

Doumbouya hasn’t made his NBA debut because of a blow to the head he sustained. He hasn’t practiced with the Pistons this week but got a workout with the Grand Rapids Drive on Friday.

It’s been an extended time in the concussion protocol probably because Doumbouya, 18, is younger and concussions tend to be treated more conservatively with younger players. Studies have shown that high school students are more vulnerable to brain injuries and they may take longer to recover from them.

His return to the court with the Drive indicates that he could be out of the protocol and be on the active roster for either Saturday’s game against the Brooklyn Nets or Monday at the Washington Wizards.

Casey's status

Coach Dwane Casey missed Friday’s shoot-around and pregame media session because of an illness. He was expected to be on the bench for the Bulls game Friday night but staff members didn’t expect him to miss an extended period.

Pistons vs. Nets

Tip-off: 7 Saturday, Little Caesars Arena

TV/radio: FSD/WWJ 950

Outlook: The Nets have struggled out of the gates, but Kyrie Irving is in midseason form, averaging 35.3 points, 6 rebounds and 6.3 assists and shooting 40 percent on 3-pointers. The Pistons will be playing their third game in four nights.

Twitter: @detnewsRodBeard