Backe, 31, came to Spring Training competing for a spot in the starting rotation, but he strained an intercostal muscle in early March and wound up missing two months. The injury opened the door for Russ Ortiz to seize the final spot in the rotation.
"We were hoping he could go to Triple-A," Wade said. "We had talked about that Saturday night, and [assistant general manager] David Gottfried talked to [agent] Brian Grieper a couple of times over the weekend, and we thought it was headed in that direction. When we got the form back today, it indicated he rejected the assignment."
Backe made six starts between Round Rock and Double-A Corpus Christi on a Minor League rehab assignment this year before rejoining the Astros and pitching mostly out of the bullpen. He appeared in five games (one start) and allowed 21 hits, 15 earned runs and five homers in 13 innings.
"We wanted to give him a chance to come in and compete in Spring Training," Wade said. "He had the strain and missed all of Spring Training. Some of the decisions we had hoped to be able to make in Spring Training got pushed into the season. Ortiz stepped up and won the job and at that point [Jose] Capellan was playing well and as the season progressed, other guys stepped up."
A native of Galveston, Texas, Backe was acquired by the Astros on Dec. 14, 2003, in exchange for Geoff Blum and quickly became a fan favorite. He went 5-3 in '04 in mostly a relief role, before going 10-8 in the rotation in '05 and helping the Astros to the World Series. He struggled with injuries in '06 before having Tommy John elbow ligament replacement surgery, which cost him almost all of the '07 season.
He came back healthy in 2008, but didn't pitch well. He made 31 starts and was 9-14 with a 6.05 ERA, leading the league in earned runs (112) and home runs (36) allowed.
But Backe saved his biggest moments for the brightest stage.
In Game 5 of the 2004 National League Championship Series, Backe held St. Louis to one hit over eight scoreless innings in a game the Astros eventually won on Jeff Kent's walk-off homer in the ninth. He held St. Louis to two hits and one run in 5 2/3 innings in Game 4 of the 2005 NLCS and delivered in the World Series that year, throwing seven scoreless innings against the White Sox in Game 4.
Backe on Friday expressed some frustration at not being able to rejoin the rotation when he returned from his Minor League rehab, but Wade said nothing was promised.
"I went to Brandon right away when he got hurt in Spring Training, and I knew that he was frustrated and talking to the trainers he was trying to make things happen that weren't going to happen," Wade said. "I said 'Back off and relax. This has to run its course.' We sent him out on the rehab assignment, and our expectations at that point were that he was going to be in the rotation.
"At some point, you have to take your heart out of the process and use your head, and we just felt when you start talking about [Felipe] Paulino and other guys in the rotation, there really wasn't anything for him to be other than what I refer to as the Maytag repair man, the role that [Brian] Moehler had at the beginning of last season before he got his chance in the rotation.
"He was victimized somewhat by his performance last year, but more than anything he was victimized by his injury in Spring Training and the fact other guys snuck up."
The departure of Backe leaves the Astros with only three remaining players from their 2005 World Series team -- Lance Berkman, Roy Oswalt and Wandy Rodriguez.