Agger broke down in tears and pleaded with Liverpool management to let him leave, per Darren Lewis at the Daily Mirror.
To cover the hypothetical scenario of Liverpool targeting Dominguez, here is a scouting report on the 25-year-old, 6'3", 183-pound Spaniard.
Rodgers prefers classy ball-playing defenders.
"When he [Agger] has the ball he's a wonderful technician," Rodgers said in 2012, per the Liverpool Echo. "He understands when to step in, when to make the pass."
Dominguez is a stylish left-footed defender with excellent technique and a smooth first touch.
There is no doubt he can emulate Agger in taking the ball out of defence to link up midfield.
This was illustrated in a play against Hoffenheim, when Dominguez sauntered to the half-way line and made a crisp pass to Gladbach substitute Amin Younes.
In that game, Dominguez completed 115 of 122 passes (94.3 completion percentage), per FourFourTwo.
Dominguez was superior to Agger last season in total passes, total forward passes, chances created and average pass length, per Squawka.
Capable of switching from centre-back to left-back, Dominguez's interchangeability means he fits what Rodgers seeks in a Liverpool footballer.
On the left side, Dominguez released a pass amid Schalke right attacking midfielder Leon Goretzka's pressure and curled the ball around Schalke right-back Tim Hoogland to play in Gladbach deep-lying forward Max Kruse.
That pass against Schalke is a sampling of Dominguez being one of the finest passing outlets from the back in the Bundesliga.
|League Only||Passes Per Game||P%||Long Passes Per Game||LP %|
Aside from being solid in the air, Dominguez's defending needs to improve.
He committed successive handballs against Bayern Munich.
Instead of tracking then-Bayer Leverkusen (now Schalke) right-forward Sidney Sam's run, Dominguez ball-watched.
Dominguez failed to get in front of Halil Altintop, enabling the Augsburg deep-lying forward to flick the ball past then-Gladbach (now Barcelona) goalkeeper Marc-Andre ter Stegen.
Out of position again, Dominguez was bailed out by the post when he was spun around by Hoffenheim right attacking midfielder Kevin Volland.
No Liverpool centre-back won back possession less times per game last season than Dominguez.
|League Only||Tackles Per Game||Fouls Per Game||Tackles Per Foul||Interceptions Per Game||Possessions Won Back Per Game|
Dejan Lovren's transformation from one of Ligue 1's worst defenders to one of the Premier League's in-form centre-backs is why Rodgers should consider Dominguez.
Southampton gambled on Lovren getting into rhythm and playing with a positive frame of mind.
A season later, he was sold to Liverpool for €25.3/£20 million.
Dominguez being a precision left-footed distributor means he would be a logical like-for-like Agger replacement.
Signing Dominguez will give Rodgers additional options to tinker a defence that will once again be the Reds' Achilles' heel.
Statistics via WhoScored.