Although the thought of Brett Favre wearing a different shade of green might be unthinkable, it certainly isn't unusual. There have been a number of Hall of Fame quarterbacks who have finished their careers in different uniforms.
Montana lost his starting job to Steve Young in San Francisco and was traded to Kansas City in 1993. The Montana-led Chiefs captured the AFC West title and advanced to the conference title game. The Chiefs again made the playoffs in 1994, but lost to the Dolphins in a wild-card game. Montana retired at the end of the season but set the bar high for quarterbacks finishing their careers in new homes after being with one club for a long time.
Van Brocklin played nine seasons with the Los Angeles Rams before being traded to Philadelphia in 1958. Van Brocklin had shared quarterback duties with Bob Waterfield, though he did set an NFL record with 554 passing yards in a game against the New York Yanks in 1951 -- the same year he led the Rams to the NFL title. The Dutchman was given complete control of the Eagles offense and eventually led Philadelphia to an NFL title in 1960, defeating Vince Lombardi's Packers.
Unitas, conversely, finished his playing days in San Diego after a storied career with Baltimore. In three season with the Chargers, he started just 14 games and wasn't able to recapture the magic in San Diego. In his final season (1973), Unitas passed for just 471 yards, three touchdowns and seven interceptions.
Namath went to Los Angeles in 1977 with the intent of getting the Rams past the Vikings and Cowboys. The Rams started 2-1 under his leadership, but he finished the year with just 606 passing yards, three touchdowns and five interceptions as injuries shortened his season. Namath watched Pat Haden from the sidelines, and the Rams were eliminated by the Vikings in a divisional playoff game played in rainy Los Angeles.
Here are some of the more notable players to switch teams after long, successful careers with one club:
Allen played 11 seasons with the Los Angeles Raiders and was selected as Super Bowl MVP in Super Bowl XVIII before he joined the rival Chiefs in 1993 -- along with Montana. Allen extended his legacy in Kansas City as he became the first player in league history to gain 10,000 yards rushing and 5,000 receiving.
Simpson rushed for 1,053 yards and four touchdowns in two seasons (1978-79) in San Francisco after a brilliant, nine-year career in Buffalo.
Dorsett spent the first 13 years of his career with Dallas, then finished up his final season in the NFL with Denver. He rushed for 703 yards (the second-lowest output of his career) and five touchdowns (tied for second-lowest) in 1988 for the Broncos.