Asked to be physically strong at center, Heat’s Jovic working on being mentally stronger

SALT LAKE CITY — Being physically strong has been a necessity for Nikola Jovic at times such as these, with the Miami Heat without sidelined center Kel’el Ware. Being mentally strong appears to be an ongoing challenge for the 22-year-old Serbian forward, including a brutal outing in Thursday night’s loss to the Portland Trail Blazers, when all semblance of confidence appeared to be lost. “I don’t even know how to explain it,” Jovic said at Saturday morning’s shootaround at Delta Center, ahead of Saturday night’s game against the Utah Jazz. “I want to play good. I’m not making shots right now, and I get a little bit down on myself....