They still had coverage skills, and their ability to set defenses from a wider scope, match up with slot receivers and tight ends, and fearlessly take on running backs near the line of scrimmage made them valuable.
And they prospered.
Now, teams aren't waiting for cornerbacks to grow older to consider making the switch, as the Arizona Cardinals showed last season by moving fourth-year pro Antrel Rolle to free safety, where he transitioned, with success, alongside two-time Pro Bowl strong safety Adrian Wilson.
The trend is to find cover safeties who not only protect against the deep ball and disrupt crossing routes but also deliver a blow that makes running backs and receivers tread lightly at the second and third levels of the defense.
"The safety position is becoming more and more of a corner position," New England Patriots coach Bill Belichick said. "There were times when some of the safeties, particularly the strong safeties, fit more like linebackers than they did as defensive backs. The demands of that position have changed."
General managers, scouts and coaches have combed the college ranks for versatile defensive backs whose toughness and athleticism can meet the criteria for the evolving dynamics of secondary play. Maybe more than any other position, defensive backs were heavily scrutinized during their workouts on the final day of the NFL Scouting Combine.
Footwork, the ability to change directions and ball-tracking skills were crucial to show in workouts. Some of those traits might not show up on film because certain players, such as Ohio State cornerback Malcolm Jenkins, weren't tested by opponents very often.
Jenkins, a rugged, do-it-all type, might have more teams looking at him as a safety instead of a cornerback after his 4.53-second 40-yard dash Tuesday at the combine didn't even rate in the top 10 among all defensive backs. Jenkins' speed was a question that teams wanted answered, and by running slower than desired, he could have hurt his draft status and slipped out of the upper echelon of defensive prospects.
Still, safeties need to be fast, too.
Oregon's Patrick Chung and Western Michigan's Louis Delmas, two of the more highly rated safety prospects, have played different positions in the secondary, which makes them all the more appealing to NFL teams, especially because they're also bell ringers.
"I was a rover, so it was pretty much corner, strong safety, free, linebacker all mixed into one," Chung said about how he was used in college. "I'm not limited at all."
Safeties used to be pigeon-holed and viewed, along with defensive tackles, as the least-valued position on defense.
Strong safeties were big hitters who weighed 220-plus pounds and served as fourth or fifth linebackers. Free safeties were, and pretty much still are, cerebral signal-callers who played center field in pass coverage.
Four of the top five interception leaders in 2008 were safeties. Reed led the NFL with nine picks, and Green Bay's Nick Collins, Tennessee's Michael Griffin and Polamalu each had seven. Green Bay's Charles Woodson, the lone cornerback in the top five, also had seven.
Safeties typically weren't drafted in the first round, but the tide is turning. In the past three drafts, eight safeties have been first-round selections -- four in 2007 (LaRon Landry, Michael Griffin, Reggie Nelson and Brandon Meriweather). Three of those eight were top-eight picks (Landry, Michael Huff and Donte Whitner).
While the highest-rated safety prospects in this draft are considered late first-rounders or early second-rounders, Delmas, Chung, Alabama's Rashad Johnson and Missouri's William Moore all could emerge as immediate impact players.
"Ideally, we'd like to get to a situation where you have interchangeable safeties," said Atlanta Falcons general manager Thomas Dimitroff, whose expertise as a college scout was evaluating defensive backs. "Maybe one guy is the strong safety, but you can flip it. Troy Polamalu and Ed Reed, those guys are great football players who set the benchmark. It's not easy to find those guys year in and year out, but those are the type of guys that we are ultimately looking for at the safety position."
One of the main reasons that teams are trying to find dual-role safeties is so they can better disguise defenses.
Teams that routinely bring the same safety toward the line of scrimmage when putting eight defenders "in the box" tip off offenses and allow audibles to be called and the scheme to be exploited. If the same safety comes on blitzes most of the time, the same can happen.
Teams also know which safety is weaker in coverage and try to match him up with a more athletic tight end, a shifty running back or a slot receiver.
Free safeties used to be viewed as some of the lightest hitters in the secondary, and offenses tried to put them in situations to make tackles on cutback runs. That perception has changed as free safeties such as Indianapolis' Antoine Bethea, Pittsburgh's Ryan Clark and Rolle laid the wood just as violently and frequently as their strong-safety counterparts.
More offenses also are using three- and four-receiver sets on first and second downs, forcing defenses to play nickel packages or leave themselves exposed to potential mismatches with strong safeties and/or outside linebackers.
If a defense can mask schemes, blitzes and coverages by moving around one safety or the other or by playing two-deep coverage, pre-snap reads are tougher for quarterbacks to make. Having safeties with similar skills makes executing the defense that much easier.
"There is a lot of variety in your coverages," Dimitroff said to that point. "I think it's something that usually will keep the offenses guessing. I'm a lot more apt to evaluate a player with the ability to cover as well as have the ability to come up and stick his nose in there and be an aggressive run-stopper guy."
Another shift regarding hybrid-type safeties is the body types of this season's prospects. Most have cornerback measurables, between 5-11 and 6-1, and only a handful weigh above 220. Moore, a highly regarded prospect, weighs 221, and at the Senior Bowl, there was some thought that his eventual position could be outside linebacker.
There's always some concern that some of the smaller, punishing safeties could have durability issues, as Sanders does, but that's where evaluators must determine if a player can add weight through training or has the body type to sustain that type of play.
"I think some of those hybrid guys have played corner and safety," Belichick said. "What his best fit is for a team, where he's most valuable, is certainly an interesting discussion for all teams."