Bell's been on the 40-man bubble. It finally popped.
Exposito, 25, is a career .268/.324/.420 hitter in seven minor league seasons, all of them spent in the Red Sox's farm system. He was a 31st-round pick in the 2005 First-Year Player Draft.
Bell, 25, batted .200/.221/.264 in 79 games with the Orioles in 2010 and 2011. He was 3-for-32 with two doubles, a home run, three RBIs, two runs scored, seven walks and eight strikeouts at Triple-A Norfolk this season.
Bell hadn't been playing third base. He served as the Tides' designated hitter and made starts at first base and right field.
The Orioles acquired Bell and pitcher Steve Johnson from the Los Angeles Dodgers on July 30, 2009 for left-hander George Sherrill.
Exposito can join John Hester at Norfolk. Ronny Paulino was supposed to be down there, but he's become Matt Wieters' backup while Taylor Teagarden remains on the disabled list.