In 2012, the Indianapolis Colts got lucky.

Andrew Luck was available as the first pick in the draft. General manager Ryan Grigson surrounded him with a great stable of young draft choices, including tight ends Coby Fleener and Dwayne Allen, wide receiver T.Y. Hilton and running back Vick Ballard. The Colts rebounded with three straight division titles and three 11-win seasons, including last season's run to the AFC Championship Game.

From the outside, though, it seemed a little strange to see the Colts sign six new starters this offseason whose average age is 31.2. Frank Gore, Andre Johnson, Todd Herremans, Trent Cole, Kendall Langford and Dwight Lowery join what was already the league's oldest roster in 2014, with an average age of 27.5, according to Elias.

Andre Johnson is one of several veteran additions the Colts made to their roster this offseason. Kyle Terada/USA TODAY Sports

What's clear is the biological clock is ticking on the Colts, even though Luck is only 25 years old. It might not be now or never for Luck to get to his first Super Bowl, but the Colts could be heading down the path of five other franchises that have quality quarterbacks. Teams that don't hit on two or three starters in each draft class eventually suffer roster decay -- and that's the position in which the Colts currently find themselves.

The Falcons are a recent cautionary tale.

In 2008, Atlanta started their roster reconstruction by taking Matt Ryan at No. 3 overall, and then selecting Sam Baker, Curtis Lofton, Harry Douglas, Thomas DeCoud and Kroy Biermann in the draft and signing Michael Turner at running back. The next year, they traded for tight end Tony Gonzalez . By 2010, the Falcons were 13-3 and won 26 games over a three-year period.

But drafts from 2010 to 2012 didn't successfully fill the roster attrition that happens to every team after the first three to five years. Despite having an elite quarterback, the Falcons have won just 10 games over the past two seasons. Similar things have happened to the New Orleans Saints, Carolina Panthers, New York Giants and Chicago Bears in recent seasons (although the Bears' quarterback situation isn't nearly as strong as the aforementioned teams).

This is a critical season for the Colts. Their 2013 and 2014 drafts haven't filled needs on defense. Bjoern Werner started 15 games at linebacker last year, but he wasn't a difference-maker while filling in for the injured (and aging) Robert Mathis. With the signing of Trent Cole at outside linebacker and Mathis' possible return by September, Werner might be a backup this season.

To fill needs and improve on defense, Grigson has relied heavily on free agency and a trade to land cornerback Vontae Davis. As of the end of last season, the only drafted starters on defense were Werner and nose tackle Josh Chapman. That's a concern, because the successful shelf life of free-agent signings is often two or three seasons. In other words, they've made some short-term fixes that could pay off in 2015 -- but the longer-term outlook is more of a concern, even with the presence of Luck, and especially if any of the Jaguars, Texans or Titans make marked improvements over the next two seasons in the AFC South.

The "win-now" approach taken this offseason is probably the right one. Luck will be the anchor of the franchise and should get a huge second contract next year, and given Tom Brady's suspension in New England and Peyton Manning's decline in play at the end of last season, there's no reason to think the Colts won't be one of the top contenders in the AFC again. That said, remember that the Colts have a lot of flexibility now because Luck is paid far less than his market value. Once you're paying full freight for a player of his caliber, it won't be as easy to shop in free agency to fill holes the draft isn't taking care of. So the potential roster drain ahead and improvements of competitors in the AFC South -- face it, the Colts have had it good in that division during Luck's tenure -- could make it hard to stay at the 11-win level by 2017 and 2018, particularly if the Colts continue to have to rely on free agency more than the draft.

The Colts don't need to be lucky this year. They need to be really, really good.