Isaiah Hartenstein returns to OKC for NBA offseason workout

Now that we're a week into September, NBA players across the league are returning to their home markets. Only a few weeks remain until training camp is here, which kickstarts the 2026-27 regular season marathon. The Oklahoma City Thunder have seen their roster fly back to their NBA homes in recent days. Isaiah Hartenstein is one. He posted a picture of the OKC practice facility on his Instagram story. The Monday social media post shows that the 28-year-old is ready to roll for his third year on the Thunder. He signed a three-year, $75 million contract extension this summer that keeps him there through the 2028-29 season. If you're trying to figure out when and where most players go through their development, point to the summer. The ample leisure time that the four months provide helps guys have a long runway to work on their craft. During the season? Not so much. You're either traveling or playing a game practically every night for seven-plus months. Since Hartenstein arrived, he's easily been OKC's best outside addition in franchise history. The seven-footer has enjoyed his best years on the Thunder. Both on an individual and team level. He's been a double-double machine since his arrival and has cemented his spot as an NBA starter. Of course, Hartenstein helped the Thunder bring home the 2025 NBA championship. Alongside Alex Caruso, both veteran additions from the 2024 summer immediately paid dividends as OKC went on to win the Larry O'Brien trophy in their first year. And almost did it again in their second year despite awful injury luck. By the end of the 2026 NBA playoffs, Hartenstein has proven to go from a luxury to a necessity. The Thunder sacrificed other parts of their roster to ensure he'd return for another season. Even with some bumps and bruises, his frontcourt tandem with Chet Holmgren has brought OKC its best franchise success ever. Expect it to keep that formula for this upcoming year. The Thunder enter the 2026-27 season as a co-title favorite — alongside the San Antonio Spurs. Even with a recast of complementary pieces, Shai Gilgeous-Alexander, Jalen Williams and Holmgren should keep them in the title picture for the foreseeable future. Considering how loaded most West frontcourts are, Hartenstein's size is a must-have. This article originally appeared on OKC Thunder Wire: Isaiah Hartenstein returns to OKC for NBA offseason workout