The two experienced Premier League and European full-backs would certainly add quality and know-how to Rodgers' young squad.
However, the obvious problem is that both are north of 30 years old—Cole is 33 while Sagna is 31.
The full-back areas at Liverpool have been an issue for Rodgers all season. Long-term injuries to first-choice duo Glen Johnson and Jose Enrique haven't helped, while Aly Cissokho has failed to impress on his loan spell from Valencia.
Of the full-backs used at Anfield this season, youngster Jon Flanagan has been the most impressive—on both the left and right side.
Johnson's future is in doubt due to his contract situation, as explained by James Pearce of the Liverpool Echo, and the left-back position has been a long-running issue at Anfield, as explained by Aaron Cutler of This Is Anfield.
Rodgers confirmed last summer, via Liverpoolfc.com, he was looking to strengthen at left-back, hence Cissokho's eventual arrival, and will seek to sign a long-term solution to the problem.
It would make economic sense for Liverpool to allow Johnson to leave in the summer, collecting a fee before his contract expires the following year and removing one of the club's highest earners—hence Liverpool's reported interest in the likes of Barcelona's Martin Montoya, as per the Daily Mirror.
What Rodgers needs is to replace Enrique and Johnson with younger players who can provide long-term solutions to each side of his defence, with players such as Flanagan providing excellent cover on either side and playing a fair share of games, especially with European competition hopefully on the horizon.
Age vs. Experience
That desire for long-term solutions is a huge part of Liverpool's strategy. Throughout their squad are players yet to reach their prime: Philippe Coutinho—21; Raheem Sterling—19; Daniel Sturridge—23; Jordan Henderson—23; Mamadou Sakho—24.
However, with a squad made up so heavily of young players, there is also a need to bring in older players to aid their development and provide much-needed experience around the club. Hence the signing of Kolo Toure last summer.
A squad made entirely of players who have never won a title between them is far less likely to go and win a title than a squad that consists of a sprinkling of veterans who know what's required to do so, having done so themselves.
Therefore, Sagna and Cole, taken in isolation could provide that experience. The signing of one or the other seems more logical than both, with that one then providing cover for perhaps two newly acquired, younger full-backs.
@thisisanfield Neither. Both on the wrong side of 30. Need FBs we can build around, not old guys wanting one more big contract.— Kevin Schummer (@kevinschummer) February 19, 2014
The likelihood of either Sagna or Cole arriving as first-choice players for the starting XI appears remote, just as it was with Toure.
This is due to the physical requirements of the role of the full-backs in modern football, as explained by Sean Ingle in The Guardian.
"The modern full-back is required to sprint and attack far more than he did a decade ago," explains Ingle, asking of Cole, "Is it any wonder the 33-year-old Chelsea defender isn't quite the player he once was?"
The role of the attacking full-back is especially true to the desired style of Rodgers' Liverpool team. It's also an explanation for why Martin Kelly, a player who hasn't started a Premier League game since September 2012, has struggled to return to the side since long-term injury.
The position is now the most physically exhaustive on the pitch—two 30-plus players are not going to solve it for Rodgers.
@thisisanfield new over 30 players for most athletic position on the pitch? No thanks.— Dara Ryder (@dararyder) February 19, 2014
Ultimately then, with Sagna or Cole only arriving to provide cover and experience, Liverpool will not be looking to offer exorbitant wages.
Reports of a "substantial offer" for Sagna appear to be what is often known as "agent talk" in the murky world of footballer transfer stories. Liverpool are hardly going to ship out 29-year-old Johnson due to his wages, then sign 31-year-old Sagna on high wages.
Liverpool are now savvy in the transfer market, they do not go above their predetermined value of a player and won't offer wages to players who aren't aligned with their status within the squad.
The question becomes more whether either player would move north from London to sign for a club offering an opportunity to join a "project" rather than a big-money move abroad to somebody such as Paris St-Germain.
Unlikely, I'm sure you'd agree.
Liverpool's interest may be genuine, but both seem like reports created to force other clubs into offering the player lucrative deals.
If either of Cole or Sagna were to arrive, it would be a surprise, but stranger things have happened.