Jets edge rusher Haason Reddick, then with the Eagles, during...

Jets edge rusher Haason Reddick, then with the Eagles, during an NFL against the Giants on Jan. 7 at MetLife Stadium. Credit: ASSOCIATED PRESS/Vera Nieuwenhuis

Haason Reddick was back in the Jets’ building on Monday for the first time in more than six months. His holdout is officially over. Now he will start getting ready to help this floundering team.

The Jets have lost four straight games for various reasons. The offense is underperforming and not taking care of the football. The defense is not getting enough stops, is not stopping the run and rarely takes the football away. Reddick eventually could help in those areas.

“As he starts to learn our defense and get integrated in what we do, he’s probably going to be more of a pass rusher,” interim coach Jeff Ulbrich said. “In time, he’s a guy that has absolutely the ability to play every down and help us in every way.”

The Jets acquired Reddick from the Eagles in March. The two-time Pro Bowl edge rusher showed up for his physical on April 1 and had been absent ever since because of a contract dispute.

Reddick’s former representative, CAA, dropped him two weeks ago. He hired Drew Rosenhaus and Ryan Matha, and they reached a deal with the Jets on a reworked contract over the weekend.

The new deal will pay Reddick his remaining base salary of roughly $8.8 million. He also will be able to recoup the $12 million in fines he’s accrued with some incentive-based bonuses.

Reddick underwent some physical evaluations on Monday and could begin practicing with the Jets on Wednesday.

Ulbrich isn’t ready to commit to Reddick making his Jets debut on Sunday in New England just yet. He hasn’t played in nine months.

“I think it’s a little too early to say that,” Ulbrich said. “We got to see what he looks like. He’s in great spirits. He’s in great shape. He’s got to get out there and spend some time with us first for us to make that decision.”

Ulbrich said something similar about Davante Adams, whom the Jets acquired from the Raiders last week. Adams played all but two offensive snaps in Sunday night’s 37-15 loss to the Steelers. But he had a training camp and played games this year.

The Jets believed Reddick would have a big impact and improve their chances of making the playoffs, and now they could use his help. He totaled 50.5 sacks and forced 13 fumbles in the previous four seasons. The Jets have totaled three sacks and no takeaways in their last two games.

Ulbrich, who also is the Jets’ defensive coordinator, said he doesn’t anticipate the players holding a grudge against Reddick for deserting them to this point.

Defensive tackle Solomon Thomas said, “We’re super-excited about Haason” and not upset about the length of the holdout.

“Haason’s going to fit right into this locker room,” Thomas said. “He’s going to be a guy who plays hard. He’s going to be a guy who gets the quarterback down and he’s going to be a guy who creates turnovers. His statistics of getting the ball out are crazy.

“This locker room isn’t a hostile environment. No one has hatred about him for the time he missed. Nobody is looking at him sideways ... All that matters is that he’s here and he’s our teammate now. We’re excited about that. We’re happy for him, we’re happy for this team and he’s going to make this team better. That’s really all that matters.”

Linebacker Quincy Williams said he spoke to Reddick on Monday.

“He’s excited he’s here, and on top of that, he’s very excited to get into the playbook so he can start helping us get some Ws,” Williams said.

Will McDonald is off to a fast start, leading the Jets with eight sacks, but their defense continues to spring leaks. They gave up season highs in yards (409), passing yards (260) and points (37) against the Steelers.

When Reddick is on the field, he will allow the Jets to consistently rush four players, which has been effective for them the last few years.

“He’s fired up, ready to get rolling with us,” Ulbrich said. “It’s another real productive speed element from our rush package. Excited about adding him to the fold.”

Newman injury update

Guard Xavier Newman, who left the field Sunday on a backboard and went to an area hospital after suffering a neck injury, flew home with the team.

Center Joe Tippmann, who considers Newman one of his best friends, said that scene “got to me a little bit ... I’m glad he’s all right and still praying for him every chance I get. That was something that really scared me in the time. But I’m glad he’s all right.”