It’s inevitable that current players are going to be compared to those who came before them, whether it’s their physical appearance or their style of play, but there’s actually actually a way to measure that likeness. The similarity score is a sabermetric concept introduced by Bill James in the 1980’s in order to compare active players with historical ones.
The original purpose was to determine a given player’s Hall of Fame candidacy based on whether the most similar players were already in the Hall. But we’re using the numbers today — for entertainment purposes only, of course — to project future performance of active players relative to similar retired player over a relative period of time.