The move paid immediate dividends when De Aza hit a home run in his first at-bat off Max Scherzer. It was his first career big league home run.
"I tried to do my best, tried to get a hit," De Aza said after the White Sox's 2-1 win. "Good things happened. As soon as I hit the ball and looked out there and saw it was a (homer)."
General manager Ken Williams said he's not worried about the fact Rios, whom the Sox claimed off waivers in August 2009, is making $12 million this season while De Aza was just called up from Triple-A Charlotte.
"Here's what I told (manager Ozzie Guillen): Do not worry about the size of the contracts," Williams said. "Just worry about putting the players out there on a given day that can win. The size of the contract is not Ozzie's problem. It's not (chairman) Jerry (Reinsdorf's) problem. It's not the coaches' problem. That's my problem."
Rios, 30, is batting just .208 with six home runs and 23 RBIs and is one of the main reasons the White Sox have not lived up to expectations as a contender for the American League pennant. He may see time at designated hitter for the disappointing Adam Dunn.
Guillen stopped short of calling it a permanent benching of Rios.
"Right now, I cannot say," Guillen said when asked if De Aza is his primary center fielder. "(Friday) we've got a knuckleball pitcher (Boston's Tim Wakefield) and the next two days are lefties. I'm going to make the lineup like I always make. I'm going to make the best lineup I thinks going to help this ballclub and see what happens."
De Aza, 27, was hitting .322 in Charlotte and was leading the International League with 124 hits and 190 total bases.
ESPNChicago.com's Doug Padilla contributed to this report. Information from The Associated Press was used in this report.