If Christian Pulisic ends up with Chelsea ... it'll be a monumental moment for U.S. Soccer ... so says Alexi Lalas, who tells TMZ Sports whoever lands the superstar will have to whip out the checkbook.
Depending on who you ask, 20-year-old Pulisic could land with big-time Premier League giants like Chelsea or Liverpool ... but Pulisic himself has been mum on his future come January.
Of course, other stars like Landon Donovan have played for teams like Bayern Munich and Clint Dempsey suited up for Tottenham ... so it's not uncharted territory for a Team USA player.
But, the big difference here is with the transfer fee involved ... as reports are saying it could cost clubs up to $80 MILLION to land C.P., who was just named the youngest captain in USMNT history.
We also asked Lalas who has a better chance of landing with the MLS -- Ronaldo or Messi -- and you'll wanna hear his take.