DETROIT — The lengthy negotiations between the Detroit Pistons and star center Jalen Duren didn’t leave any lingering animosity, at least not in the mind of head coach J.B. Bickerstaff. Duren, an All-NBA Third Team selection last season, agreed to a five-year, $200 million contract. There were reports during the offseason that the restricted free agent sought sign-and-trade options and even felt disrespected by the front office. Duren, who was not made available to the media, underwent a physical and other testing on Friday and is expected to start practicing as early as this weekend. Bickerstaff brushed aside any suggestion that Duren might not be fully invested in rejoining the team. “The most important thing for us was having JD back with us and I know JD wanted to be back,” Bickerstaff said. “All that stuff that was floating (around), we know what’s real. It’s a negotiating process and we went through the process and we knew he’d be back.” Duren had little leverage, other than to sign a $9.6 million qualifying offer — which expired on Thursday night — and become an unrestricted free agent after this season. President of basketball operations Trajan Langdon repeatedly stated he had no interest in dealing his starting center. Duren was eligible for a five-year contract worth up to $287 million but the fully guaranteed deal will still make him one of the top 10 centers in terms of annual salary. “There’s never been any bitterness between the group and how we feel about him and I know how he feels about us,” Bickerstaff said. Duren averaged a career-high 19.5 points last season, along with 10.5 rebounds per game on 65% shooting. He struggled in the playoffs, averaging 10.2 points as the top-seeded Pistons failed to get out of the second round.