Modric, 32, arrived at Real in 2012 from Tottenham for a reported fee of £30m, and initially struggled to settle into life in the Spanish capital.
However, since an indifferent debut season, the diminutive midfielder has developed into one of the best playmakers in Europe, winning 13 trophies over six seasons.
The Croatia international has singled out his success at Los Blancos down to his consistency, knowing one bad performance at at the European champions could end your career at the club.
"At Real Madrid you have to perform to a high level in every match because if not then it's difficult to stay there," he said in an interview with SVT Sport, as quoted by Marca.
On links with the MLS; "You never know what can happen. I still have two more years on my contract at Real Madrid and I am happy and have always said that I'd like to finish my career in Madrid if it's possible.
"But if not, then maybe one day I can see myself there [in the MLS], I think little by little, [rather than long-term]."