General manager Rich McKay and head coach Jim Mora are still looking for a primary backup to replace Doug Johnson.
"We need a legitimate No. 2 quarterback," Mora said Wednesday.
Mora and general manager Rich McKay spent the last four days in Palm Beach, Fla., at the NFL meetings, where they sought information on players to work behind Vick. The team announced Tuesday that Detmer had signed a contract, but the 12-year veteran is likely to serve as the No. 3 quarterback.
"It's still too early to tell how things will shake out," McKay said. "We might still be about two months away from getting something done."
Detmer, who is 36 and signed a one-year deal worth $775,000, has been a backup most of his career and hasn't attempted a pass since 2001. He won the Heisman Trophy at BYU in 1990 but has been a journeyman in the NFL, making stops at Green Bay, Philadelphia, San Francisco, Cleveland and Detroit.
Mora, who was hired Jan. 8 to replace Dan Reeves, will hold a three-day veteran mini-camp beginning Wednesday. Detmer, who was on the Lions' roster the last three years, can help Vick, the 23-year-old franchise star, adapt to the new offense.
Given his background working in the West Coast offense, Detmer was a good fit for Atlanta. New Falcons coordinator Greg Knapp, who held the same job in San Francisco the last three years, was the 49ers' quarterbacks coach in 1998 during Detmer's one season in the Bay Area.
Detmer also learned versions of the same offense under former Packers coach Mike Holmgren, former Eagles coordinator Jon Gruden, former Detroit coach Marty Mornhinweg and current Lions coach Steve Mariucci.
The Falcons last week met with two unrestricted free agent quarterbacks, Chris Redman of Baltimore and Damon Huard of New England. Both worked out for Atlanta officials, who could wait two months before signing a primary backup.
Jon Kitna of Cincinnati and Trent Dilfer of Seattle will draw interest if their teams release them June 2 as expected. That's the first day clubs can cut veterans without having to absorb the entire value of their 2004 salary under the NFL cap.
Atlanta is not expected to re-sign Johnson, an unrestricted free agent. He and Kurt Kittner, who is still on the roster, combined for the league's worst interception ratio.
Vick, a first-team Pro Bowl selection in 2002, missed 12 starts last year after breaking his right leg in a preseason game. The Falcons went 2-10 without Vick but finished 3-1 when he returned to the lineup.