The 22-year-old, who is nicknamed 'Little Fox', was spotted by Anfield officials during a general scouting trip to North America.
Pachuca executive director Andres Fassi has revealed that the Reds have first refusal on the player.
He said: "We have a sort of deal between the two clubs, in that Liverpool would be the first in line should the player emigrate to Europe.
"There's no formal offer yet, only interest, no verbal agreement or pre-contract."
Herrera is likely to feature at this year's London Olympics, where Liverpool will continue to monitor his progress.