The Chicago Cubs optioned outfielder Ben Grieve to Triple-A Iowa of the Pacific Coast League prior to the start of their contest with the Houston Astros on Tuesday. The 1998 American League Rookie of the year batted .250 with an RBI in 15 games for the Cubs this season. He was also 3-for-10 in pinch-hit opportunities. For his major league career, the 29-year-old Grieve has batted .269 with 192 doubles, 118 homers and 492 RBI. He has also spent time with Oakland (1997-2000), Tampa Bay (2001-2003) and Milwaukee (2004). In a related move, the Cubs recalled righthander Sergio Mitre from Iowa. The 24-year-old Mitre, who has seen major league action with the Cubs in each of the past two seasons, was 3-4 with a 4.60 ERA in eight starts for Iowa this season. Mitre is 2-5 in 15 big league games, 11 of which have been starts.