Pirates management designated Bullington for assignment on July 3 to make room on the 40-man roster for outfielder Chris Duffy, who was reinstated from the 60-day disabled list.
The Pirates had hoped that Bullington would clear waivers and rejoin the organization before other teams would claim the right-hander.
"As [it is] anytime we lose a player on waivers, we've made a strategic decision," general manager Neal Huntington said. "In Bryan's situation, we felt like we had a chance to get him through waivers. We felt other players were more worthwhile to keep on the roster."
Bullington was recalled by the Pirates from Triple-A Indianapolis earlier this season, but never made an appearance after spending 16 days on the Major League roster.
He returned to Triple-A after that period, where he started the season 0-5 with an 8.04 ERA in seven starts. He bounced back, however, to win four of his past five decisions.
"It's a great thing for Bryan," manager John Russell said. "It's just another opportunity for him to pitch somewhere else."
Bullington made a total of six appearances in a Pirates uniform. He finished with an 0-3 record and 5.89 ERA in 18 1/3 innings pitched. Bullington underwent right shoulder surgery on Oct. 17, 2005, that caused him to miss the entire 2006 season.
"Being with us, I don't know if he would have reached the plateau," Russell said. "But he was one of those guys that was looking for something to get him going. Hopefully, this will do that. We hope that he does well."
It's likely that Bullington will serve the Indians much like he did the Pirates. He is currently a Triple-A starter who could make a spot start at the Major League level when needed.
"Bryan had done an adequate job," Huntington said. "We spend a lot of time trying to get better. We spend a lot of time trying [to assess] what they presently are and what they are going to be in the future.
"In this situation, it was a tough one."
Todd Krise is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.