Gregg, 32, went 2-6 with a 3.51 ERA in 63 games with the Blue Jays in 2010. He finished tied for fourth in the American League with a career-high 37 saves and tied for second in the league with 56 games finished. Gregg is 25-33 with a 4.03 ERA with 122 career saves in 406 games over eight Major League seasons.
Gregg has saved at least 23 games in each of the past four seasons, one of only seven pitchers --- Mariano Rivera, Francisco Rodriguez, Jonathan Papelbon, Francisco Cordero, Bobby Jenks and Jose Valverde are the others -- who have accomplished that feat. In those four seasons, among pitchers who pitched at least 280 innings and did not start a game, Gregg's 8.8 strikeouts per nine innings are the fourth most in baseball, behind only Carlos Marmol, Jonathan Broxton and Heath Bell.
"Kevin has demonstrated that he can close in this division," said Andy MacPhail, the Orioles' president of baseball operations. "One of our issues in the beginning of the year was we did not have a healthy [Koji] Uehara, [Jim] Johnson and [Michael] Gonzalez. I felt it was important that we had someone who was healthy and durable to go along with that group."
While manager Buck Showalter has maintained that no one will be simply handed the closer's role, Uehara is the front-runner entering Spring Training, and Gregg was made aware that he would be facing stiff competition for the role before signing.
But given Uehara's injury-prone past, the O's have a very capable backup option in Gregg, who had offers from three or four other teams, at least one of which was for the closer spot.
"Koji's kind of the heir apparent and front-runner, [Gregg] knows that," Showalter said. "To say that he's our closer, no. To say that he has the opportunity, yes.
"[Gregg is a] competitive guy. I love the fact that he doesn't shy away from the AL East. Some guys can't wait to get out [of the division]. He defends himself against left-handers, he's another one of those guys [in the back end of the bullpen]. [It's a] nice, cohesive unit -- Gonzalez, Koji and JJ a little bit. There's so many what-ifs [injury-wise]."
With the addition of Gregg, the O's have 39 players on their 40-man roster.
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.