"It was more just a function of opportunity," Antonetti said. "We didn't have an immediate Major League opportunity for Daisuke. He'd been throwing well in Triple-A and thought that he may have a better opportunity elsewhere. So he asked for his release and we granted it."
The Indians signed Matsuzaka in February, released him on March 24, then re-signed him to a new contract two days later to keep him in the organization. The 32-year-old starter went 5-8 with a 3.92 ERA in 19 starts for Triple-A Columbus this season.
Matsuzaka allowed five runs on eight hits in four innings for Columbus on Monday, but he had been on a strong run prior to that outing. In his previous seven starts, the right-hander posted a 2.20 ERA with 39 strikeouts and eight walks across 49 innings (an average of seven per start).
A calf injury hindered Matsuzaka's chances of cracking Cleveland's Opening Day roster in Spring Training and an oblique issue cost him time during the Minor League season.
"There were a number of things that went wrong physically," said Indians manager Terry Francona, who managed Matsuzaka during their days with the Red Sox. "It kind of pushed him back. So he was never really a candidate, just because he wasn't pitching. Lately, there's been some games where he's pitched pretty well at Triple-A, but there wasn't a need.
"It's good for him to log innings for his career. Giving him a chance to go somewhere is maybe good for him."
Matsuzaka went a combined 33-15 with a 3.72 ERA in 61 outings between the 2007-08 seasons for Boston. Since that strong start to a much-hyped Major League career, the righty has endured inconsistent results and injury. He went 17-22 with a 5.53 ERA over the '09-12 seasons (296 innings) and underwent Tommy John surgery on his throwing elbow in June of '11.
"We knew that he had work to do," Antonetti said. "We do feel like Daisuke is in a better spot now at the end of the year than he was at the beginning of the year. Hopefully he can get that Major League opportunity and go help someone."
Jordan Bastian is a reporter for MLB.com. Read his blog, Major League Bastian, and follow him on Twitter @MLBastian. This story was not subject to the approval of Major League Baseball or its clubs.