Lopez received his most extensive activity as a closer with the White Sox Triple-A Charlotte affiliate. He recorded 12 saves and posted a 0.55 ERA in 26 appearances. The White Sox traded Lopez to Boston on June 15 for right-hander David Riske. Lopez proceeded to win a World Series ring with the Red Sox the following season.
"It was a learning experience," Lopez said of his stint with the White Sox, who completed a two-game Interleague series with the Giants on Wednesday. "The stuff that I did then when I warmed up is stuff that I do now. I work on getting the ball down instead of throwing to spots."