With the move, the Cubs now have 12 pitchers on the 25-man roster.
This is Fox's second stint with the Cubs, having gone 5-for-12 with two doubles and two RBIs in eight games from May 27-June 9. He was 5-for-6 with two doubles and an RBI as a pinch-hitter.
Fox was batting .409 with 44 runs, 14 doubles, three triples, 17 homers and 53 RBIs in 45 games for Iowa. He leads the Minor Leagues in batting average, on-base percentage (.495) and slugging percentage (.841).
Since he was optioned to Iowa on June 9, Fox has reached base safely in three of four games, going 3-for-13 with three runs, a triple, two RBIs and four walks.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.