Felipe Vazquez was an All-Star the past two seasons as the Pirates' closer, but he was arrested in September on felony charges stemming from an alleged sexual relationship with a minor.
Kela converted 24 of 25 save opportunities for the Texas Rangers in 2018 before being traded to the Pirates in late July.
Kela says he's excited about getting another chance to close, and he's eager work with his new manager.
"[Shelton's] message is to just have fun,'' Kela said. "He's waited a long time to be a manager. He has that passion and I think it's going to resonate through the whole clubhouse. It's a new feel. It's a new vibe. I think it's what everyone wants. We want to change the narrative of everything.''
The Associated Press contributed to this report.