The 49-year-old was designated for assignment by the Rockies last week and subsequently cleared waivers, allowing the Orioles to sign Moyer for his second stint in the organization.
"I think he's committed to two or three starts and we will see where he's at," manager Buck Showalter said of the terms of the deal. "From what I understand talking to [executive vice president of baseball operations Dan Duquette], he mentioned his name a few days ago."
Duquette also reiterated that the Moyer signing will be more of an audition, as he will get a few starts and the team will evaluate him at that point.
"He's not that far removed from the [Tommy John] surgery, so there's a chance that he will regain his previous form by continuing to pitch," Duquette said. "A lot of veteran pitchers, sometimes it takes a little bit longer to get into length of the season until they come around. So we will see if that's the case with Jamie. He has won a lot of games, is a good role model and has had some success.
"We agreed to give it a few starts, so he's a veteran player, he will know. And if he can help us, he can help us."
Moyer, who was invited to Spring Training by the Rockies after missing last season, made the starting rotation and went 2-5 with a 5.70 ERA before being designated.
He is the oldest pitcher in Major League history to record a win. In Moyer's last victory on May 16, a 6-1 win over the D-backs, Moyer allowed one earned run on six hits while striking out five over 6 1/3 innings.
Moyer spent 1993-95 with the Orioles and went 25-22 with a 4.41 ERA in 75 games (66 starts). His 25-year baseball career also includes time with the Seattle Mariners, Chicago Cubs, Texas Rangers, St. Louis Cardinals and Boston Red Sox. Lifetime, Moyer is 269-209 with a 4.25 ERA over 4,074 innings. He made one All-Star Game appearance, in 2003.