Astros general manager Jeff Luhnow made an announcement Sunday morning during a news conference at Minute Maid Park that Tony DeFrancesco as been named the club's interim manager a day after the firing of Brad Mills.
DeFrancesco had been serving as the skipper of Triple-A Oklahoma City.
Mills, along with hitting coach Mike Barnett and first-base coach Bobby Meacham, were fired by the club late Saturday night following the club's 12-4 loss against the Arizona Diamondbacks.
The Astros fell to 39-82 on the season, which includes a 12-48 record on the road and a lopsided 3-24 record during the month of July.
Mills posted a 171-274 record over slightly less than three seasons as the Astros' manager.
The former Boston Red Sox bench coach was hired in October 2009 by former general manager Ed Wade under the ownership of Drayton McLane Jr. -- thus making him a holdover with owner Jim Crane, president and CEO George Postolos and Luhnow now at the helm.
Although the results on the field make Mills' tenure look less than favorable, it's hard to place a tremendous amount of blame on him.
The organization has made it a priority over the last few seasons to hold a firesale in an effort to dump payroll while restocking its farm system.
Mills had to work with a limited amount of major league talent during his tenure due to the club's decision to trade Roy Oswalt, Lance Berkman, Michael Bourn, Hunter Pence, Jeff Keppinger, Carlos Lee, Brett Myers, Wandy Rodriguez, J.A. Happ, Brandon Lyon, David Carpenter and Chris Johnson.
Pettini served as Tony LaRussa's long-time bench coach with the St. Louis Cardinals prior to joining Luhnow (formerly with the Cardinals organization) in Houston this season.
Maloney is another product of the Cardinals' system.
The former minor league first baseman and outfielder spent the 2011 campaign as the skipper for Triple-A Memphis (his fifth straight for St Louis' farm club) before being hired as Mike Matheny's first-base coach on the major league staff.
Riggleman, who previously managed the San Diego Padres, Chicago Cubs, Seattle Mariners and Washington Nationals, is currently serving as the skipper of the Pensacola Blue Wahoos.
Pensacola is the Double-A affiliate of the Cincinnati Reds.