Following FIFA's approach at the men's and women's World Cups, England's referees body said in July officials would add on the exact time lost to goal celebrations, substitutions and injuries.
The aim is to increase the time the ball is in play, with games now routinely going beyond 100 minutes in total.
Manchester City midfielder Kevin De Bruyne, Manchester United defender Raphael Varane and global players' union FIFPRO have criticised the new approach, saying it will increase player workload in an already packed schedule.
"It's absolutely absurd," former AC Milan and Croatia midfielder Boban told reporters in Monaco.
"Regarding player welfare, it's some kind of small tragedy or big tragedy because we are adding almost 12, 13, 14 minutes.
"When you play 60, 65 minutes - I can speak from my experience, especially as a midfielder - when you get tired, it's the last 30 minutes of the game. And then somebody comes and adds another 15 minutes.
"How often we have spoken critically about the calendar and too many games. We are not listening to players and coaches ... It's crazy. It's too much, so we will not do this. Our guidelines are different."
UEFA's chief refereeing officer Roberto Rosetti backed Boban and said the governing body had been working for five years to increase the time the ball was in play during its competitions.
"There is something more important than the accuracy of additional time," Rosetti said. Why do people like the Champions League so much? Because it's intensive, it's fantastic, the players never stop.
"We tell our referees to speed up the restart of play instead of focusing on stoppage time."
In a statement on Thursday, FIFPRO said it welcomed UEFA's approach, adding that the European governing body was listening to "players and unions".
"This is an excellent player-centric decision which will make a difference for footballers across Europe," FIFPRO Europe President David Terrier said.
"The fruitful cooperation with UEFA underlines our shared commitment to enhancing player welfare."
England's Professional Footballers' Association (PFA) chief Maheta Molango, who previously criticised the regulations, said player workload was a key issue for players.
"It is totally unsustainable. It's clear they are having to make really difficult decisions about how to protect their own health and fitness," Molango added.
"The comments from (Boban) show that he gets it."
