Fielding was pushed all the way over eight rounds by tough Czech Karel Horejsek on Saturday night, eventually prevailing via a score of 79-74, improving his record to 26-1.
The Liverpool super-middleweight is now on the cusp of a fight with WBO titlist Ramirez (37-0-KO25) as the Mexican looks to make the fourth defence of his belt.
"We've been in talks this week. It looks like it will take place in June, we are just working on the deal now, it's quite close," promoter Hearn told Sky Sports.
"Fielding has worked his way up the rankings and earned his shot.