Walker Kessler is hardly the first NBA player to post a video like this. The new Los Angeles Lakers center is in the gym, lifting weights, cold-plunging, doing agility drills and slamming basketballs. He may, though, be the first to share a summer workout mixtape video to the twangs of a Zach Bryan ballad.The details with Kessler all matter. He’s the biggest swing the Lakers took this summer, the richest bet they made. He cost the Lakers $130 million, two unprotected first-round picks and two unprotected first-round swaps.Kessler, who turned 25 Sunday, played in just five games last season and 58 the year before, numbers that are, in part, explainable in the context of the Utah Jazz’s conservative approach to injuries while aggressively pursuing the best possible draft lottery odds. But it’s also one of the key reasons why some rival scouts and executives have been critical of the Lakers’ plan.“He better be good,” said one Western Conference scout who, like other sources in this story, was granted anonymity to discuss teams’ strategies. The words were cloaked in an “or else” tone.Part of the reason so much hinges on Kessler is the way the Lakers and Luka Dončić prioritized him. Another part is that the Lakers have only Kevon Looney as a backup. Sandro Mamukelashvili and Jarred Vanderbilt are in pencil further down the Lakers’ depth chart, but neither would be capable of playing center on a full-time basis should they need to.Looney played only 21 games last season with the New Orleans Pelicans, in his first year outside of Golden State. He played 314 total regular-season games in the four prior seasons — a remarkable run of durability, with only Jonas Valančiūnas appearing in more games at center. For Looney, who entered the NBA with a hip injury, the games and minutes crashing the glass and setting bruising screens for the Warriors had to have some cumulative impact, limiting his mobility and, last season, his availability.