He's generally regarded as one of the greatest quarterbacks to ever play the game.

He set numerous passing records, led his team to championships, won multiple MVP awards and was the face of the Colts' franchise for more than a decade.

But now, with all those seasons of glory and greatness behind him, he's gonna have to move on and play for another team? Gosh, that just doesn't seem right, does it?

Yeah, that sure is a lousy thing to do to a great guy like him. Of course, we're talking about ... Johnny Unitas.

Yep, in the often fickle, what-have-you-done-for-me-lately world of professional sports, great players often change teams during their careers.

Sometimes, it's their own choice. Other times, their forwarding address is forced upon them by the franchise they've spent most of their careers in a starring role with.

This past week, the Indianapolis Colts decided to dump their longtime star quarterback, Peyton Manning, who missed the entire 2011 season following two neck surgeries and was due a $28 million bonus if he was still on the team's roster by last Thursday's deadline.

Instead, they released the four-time league MVP on Wednesday.

It certainly marked the end of an era for the franchise but, hey, the Colts have definitely been down this road before.

They did it first with Unitas, the iconic QB who was a three-time league MVP and led the team to three NFL titles back when the Colts were based in Baltimore.

But then the years and injuries caught up with Unitas, the original, seemingly always cool-and-calm master of the two-minute drill. The bow-legged guy with the crew-cut and black, high-top cleats — heck, it was the legendary heroics of ol' No. 19 that drew me to football as a kid back in the early 1960s — got shipped off to the San Diego Chargers in 1973.

Johnny U. spent one forgettable season with the Chargers before calling it a career. And he never looked quite right in that Chargers' uniform with those lightning bolts on his helmet and the shoulders of his jersey.

It'll be much the same for Manning, arguably the game's best quarterback over the last decade-plus. Now a free agent, this great-gun-for-hire quarterback will be courted by several teams.

Reportedly the Broncos, Dolphins, Cardinals, Seahawks, Redskins, Chiefs and Jets are among a dozen or more teams in the mix for his services.

And you know what? No matter what Manning does from here on out, he won't look quite right wearing any team's helmet other than that of the Colts, with that familiar horseshoe emblazoned on the sides of it.

Manning, who led Indianapolis to the Super Bowl championship in 2007, certainly isn't the first — nor will he be the last — superstar athlete to switch teams during his storied career.

Joe Montana, squeezed out of San Francisco by the emergence of quarterback Steve Young's rising star, finished his Hall of Fame career in Kansas City. So did longtime Raiders' star running back Marcus Allen.

Brett Favre, who led Green Bay to a Super Bowl title, wound up playing for the Packers' arch-rival, the Minnesota Vikings, for the last two years of his stellar career. (Well, at least we think it's the last two years of Favre's career. With the perennial comeback kid, you just never know).

Other well-known pro football stars like Emmitt Smith, Jerry Rice, Joe Namath, O.J. Simpson, Franco Harris, Earl Campbell, Tony Dorsett and Bruce Smith also finished up in relative obscurity, playing someplace far from where they had achieved their star status.

The same is true for major league baseball greats like Babe Ruth, Willie Mays, Hank Aaron, Steve Carlton, Harmon Killebrew and, this year, Albert Pujols, as well as NBA stars Michael Jordan, Hakeem Olajuwon, Patrick Ewing, Scottie Pippen, Gary Payton and Allen Iverson, among others.

And, of course, closer to home, legendary Jazz power forward Karl Malone spent his last NBA season in Los Angeles, where The Mailman chased an elusive championship ring with the Lakers.

Manning's legacy is certainly secure. Even though younger brother Eli now has more Super Bowl titles (2) than his big bro Peyton (1), no one will ever doubt that the elder of these two Manning boys belongs on the short list of greatest quarterbacks ever.

Even if he winds up wearing a Cardinals, Seahawks or Dolphins helmet at the end of his career — and looks kinda weird with it perched atop his head.

email: rhollis@desnews.com