The Brooklyn Nets and LA Clippers are no strangers to NBA rumors, as both franchises have been the subject of major offseason speculation. The Nets and Clippers have some of the best rosters in the league and are major title contenders, but their respective front offices continue to push for signings that can improve the squad further.NBA Rumors: Isaiah Hartenstein on LA Clippers, Brooklyn Nets, and OKC Thunder's radar, Cleveland Cavaliers interested in re-signing himHouston Rockets v New Orleans PelicansAccording to Chris Fedor of Cleveland.com, free-agent center Isaiah Hartenstein held a workout in Las Vegas, where representatives of the OKC Thunder, Brooklyn Nets, and LA Clippers were present. The Cleveland Cavaliers themselves are interested in re-signing him, and that indicates that Hartenstein has a considerable market for him in the 2021 NBA offseason.#Cavs Evan Mobley looks as advertised during Summer League, showing both his strengths and weaknesses. Lamar Stevens "100 percent" thinks he belongs. Who gets the second two-way? And hunt for rotational wing continues -- Summer League Observationshttps://t.co/KnFTfMpF9E— Chris Fedor (@ChrisFedor) August 17, 2021Hartenstein played for the Cleveland Cavaliers last season, averaging 5 points, 4 rebounds, and an assist per game, playing 18 minutes per contest. The Cleveland Cavaliers are looking for a front-court partner for Evan Mobley, who is expected to start at the power forward position. Hartenstein shot 60% from the field, and his performances last season might prompt the Cleveland Cavaliers to bring him back.The two interesting names in the mix are the LA Clippers and Brooklyn Nets, both of whom belong to the upper echelons of the NBA. The LA Clippers had an eventful 2021 postseason, reaching the Western Conference finals stage for the first time in their history. They have been active in the market lately, trading away Patrick Beverley for Eric Bledsoe.Also check out: James Harden Contract BreakdownMeanwhile, the Brooklyn Nets crashed out of the Eastern Conference semi-finals stage, succumbing to a seven-game loss against the Milwaukee Bucks. Injuries to Kyrie Irving and James Harden played a major role in the loss, as Kevin Durant was unable to get his team across the line single-handedly.The Brooklyn Nets are filling out the roster at the moment, re-signing key free agents like Bruce Brown. Despite last season's disappointment, the Brooklyn Nets go into the new campaign as firm favorites alongside LA Lakers, who formed their own 'big 3' by adding Russell Westbrook to their roster.Bruce Brown on the Nets' offseason: "We all wanted to be back. I wanted to be back. We have unfinished business for sure."Bruce then jokes that he didn't watch Kevin Durant in the Olympics: "I watched him try to dunk on Rudy Gobert, but he didn't even come close so."— Kristian Winfield (@Krisplashed) August 9, 2021What's apparent is that the Brooklyn Nets and LA Clippers are in desperate need of a center, and Isaiah Hartenstein will likely play for an NBA championship contender.Also Read: NBA Trade Rumors: Toronto Raptors to keep hold of Pascal Siakam despite interest from multiple teams