BY ANTHONY SLATERJames Harden is in Houston and Serge Ibaka is out with an injury. But you’d have a hard time convincing Spurs coach Gregg Popovich that the Big Three in Oklahoma City is lacking a third wheel. “If anybody watched our games, they watched Reggie Jackson basically be the Spurs killer any time we played them,” Popovich told reporters in advance of Monday’s series opener. In four meetings with the Spurs this season, Jackson averaged 21.2 points on 68 percent shooting.Read more on NewsOK.com