The Reds have been linked with a move for the 25-year-old for a number of weeks.
However, according to Sierra, Liverpool have finally acted on their interest. The journalist further added that Tottenham Hotspur have recently made two unsuccessful proposals to the Colombia international.
Anfield Watch Verdict
Diaz would certainly add depth and quality to Liverpool's squad.
Diaz is only 25 years of age. Therefore, it would be fair to assume that the Colombia international still has plenty of room left for improvement.
It is common knowledge that footballers lift their standards when they are surrounded by top players.