Longtime veteran starting pitcher Aaron Cook has become a free agent for the very first time in his career. The 32 year old righthanded pitcher was drafted by Colorado in the 2nd round of the 1997 draft and remains the franchise leader in wins. He has been plagued by injuries for the last few seasons and has pitched ineffectively when healthy, with a 6.03 ERA in 97 innings in 2011.
Starting pitcher Kevin Millwood, 36, also filed for free agency, and the right handed starter may garner some interest in a weak starting pitching market after his successful stint with the Rockies in 2011. Millwood was released by the Boston Red Sox earlier in the season, but found some traction with the Rockies with a 3.98 ERA in 54.1 innings. Colorado may look to re-sign Millwood as starting pitching depth for 2012.
Second baseman Mark Ellis, 34, was acquired by Colorado from the Oakland Athletics in June to fill a hole in the starting lineup. He played 70 games and hit .274 with the Rockies, and the club has expressed interest in bringing Ellis back as a starter for 2012, though at a much lower cost than his $6 million 2011 salary.
Relief pitcher J.C. Romero, 35, has also filed for free agency. The lefty reliever was released by the Philadelphia Phillies midseason and picked up by the Rockies to bolster a weary bullpen. The veteran appeared in 12 games with a 4.32 ERA, and the Rockies have also discussed bringing Romero back as relief depth for 2012.