Overbay's batting average has fallen to .228 from a high of .242 on June 10. He is on a 4-for-30 run spanning 11 games. Over the same period, Jones, who was hitless in two at-bats Monday, has gone 11-for-32 and raised his average from .229 to .251.
Pirates manager Clint Hurdle said Overbay would not start for the entire series as he works on his hitting.
"We'll use him as the game dictates, with a double-switch or pinch-hit, but I actually told Lyle that we're just going to back him off these three days and get Garrett out there, and go from there and see where that takes us," Hurdle said. "See if we can tighten things up and reignite him."
Jones, who played 112 games at first base for the Pirates in 2010, made his second appearance there this season while seeing regular playing time at the corner-outfield spots. Hurdle explained how comfortable he is with Jones at first.
"Comfortable enough to start him there," he said.