The most efficient way to build a good roster in today's NFL is through the draft.
Teams that rely too heavily on free agency either overpay for their achievement or are inconsistent from year-to-year.
The good teams - the ones that stay good for a long time - get their stars early in the draft, add depth in the mid-to-later rounds and occasionally hit a home run with a late pick.
The San Francisco 49ers and Baltimore Ravens are great examples of that philosophy. They'll be playing in the Super Bowl on Sunday with a majority of players they drafted and developed. They filled in the gaps in free agency, but the core of their young talent was home grown.
When it comes to the draft, rounds three through seven are how teams build their depth, but what's been impressive about the way the 49ers have been built – and to an extend the Ravens - is that they've hit multiple home runs in the later rounds.
San Francisco running back Frank Gore was selected in the third round in 2005 and linebacker NaVorro Bowman was selected in the third in 2010. Safety Dashon Goldston in the fourth round in 2007. All three players were Pro Bowlers this year.
Ravens Pro Bowl guard Marshal Yanda was taken in the third round in 2007.
The Detroit Lions haven't found a Pro Bowler in the later rounds since GM Martin Mayhew and head coach Jim Schwartz took over, but they have found both starters and key contributors.
Linebacker 
Defensive tackle
It's yet to be determined the impact last year's crop of picks in the third (
Unfortunately, the Lions are stilling feeling the effects of the old rookie system that still has them paying the price for taking quarterback
Of the 22 starters Week 1 vs. the Rams, the Lions drafted 12 of those and three of them –
"We're trying to find good players for the long haul,” Mayhew said after the season. “It's not just about getting ready for the first game of the season. I think that's short-sighted.
"The draft is supposed to build your team for the future, in my opinion, to get your team ready for every season to come. I think you've got to take the best players that you can find."
The 49ers and Ravens have done an excellent job with same philosophy
Of the 53 players on the Ravens' Super Bowl roster, 29 of them were acquired through the NFL draft.
The Ravens got seven of them via the first round, six in the second, three each in the third and fourth, five in the fifth, three in the sixth and two in the seventh.
The 49ers also have 29 draft picks on the roster, 10 from the first round, two from the second, four in the third, three in the fourth, two in the fifth and four each in the sixth and seven rounds.
Both the 49ers and Ravens were built through the draft and complimented those building blocks with free agents.
Mayhew and Schwartz have the same viewpoint and the team recently bolstered its scouting and personnel department with the hire of former Broncos general manager Brian Xanders to do just that.
The Lions have built their core through the top of the draft. They need to continue to do that, but hopefully hit a couple home runs - like the Ravens and 49ers have done - on days two and three.
