Average driving distances are around 300 yards on the PGA Tour but many players hit well in excess of that, meaning some courses are in danger of becoming obsolete.
The proposal by the Royal and Ancient (R&A) and United States Golf Association (USGA) would give competition organisers the option to require players to use only balls that meet maximum-distance criteria.
"You're trying to create a solution for a problem that doesn't exist. To me, it's just so bad for the game of golf," Thomas told reporters ahead of this week's Valspar Championship in Palm Harbor, Florida.
Under the proposal, which would be effective from 2026, balls will have to not exceed 320 yards with a clubhead speed of 127mph.
"If you can swing 127mph, power to you," Thomas said.
"People are running faster, so are they just going to make the length of a mile longer so that the fastest mile time doesn't change? Like, no. It's evolution."
Former US Open champion Bryson DeChambeau (29), one of the longest hitters in the sport, said it would be "the most atrocious thing that you could possibly do to the game of golf".
"It's not about rolling golf balls back, it's about making golf courses more difficult," DeChambeau said on Tuesday ahead of a LIV Golf event at the Gallery Golf Club in Tucson.
"I think it's the most unimaginative, uninspiring, game-cutting thing you could do. Everybody wants to see people hit it farther."
