Pakistan great Imran Khan fears fast bowlers "could go the way of the dinosaurs" if the international calendar retains its current congested schedule.
And the former Pakistan captain, who in 1992 led his country to World Cup glory, suggested axing 50-over cricket as a way of ensuring the "unprecedented" stress on fast bowlers was eased.
Imran, arguably the premier fast bowling all-rounder of his generation, made his remarks while giving the annual Cowdrey Lecture at Lord's here on Monday.
"Maybe we should eliminate 50-over cricket and just have Twenty20 cricket and Test cricket," he said.
"I don't believe Test cricket is the same standard as before," added Imran, who played against the fearsome West Indies pace attack of the 1980s as well as Australia's Dennis Lillee and Jeff Thomson.
The 57-year-old Imran, who since retiring from cricket has entered domestic politics, was at Lord's last week to see Pakistan lose the first of their two-Test series against Australia by 150 runs.
Defeat prompted Shahid Afridi to announce his retirement from Tests after just one game back as Pakistan captain.
Imran said Afridi was an example of a fine Twenty20 player who lacked the temperament for the five-day format.
"The only test of a cricketer is the Test match because his talent and technique is tested," said Imran, the first Pakistani to deliver a lecture named after former England captain Colin Cowdrey.
"In Twenty20, if you are very talented you can get away with it, but a good Twenty20 cricketer will not necessarily excel in Test cricket."
Meanwhile Imran said the way the international game was structured put "tremendous pressure" on bowlers.
"The stress on fast bowlers is incredible. But cricket without fast bowling is never going to be the same standard if a batsman doesn't test himself against fast bowling.
"I saw [Australia's] Shaun Tait bowl in the Twenty20s and I thought an alien had come in -- you suddenly saw batsmen hopping about."
Imran, who led the call for 'neutral' umpires, said the standard of officiating at international level had improved greatly since his day and he insisted this would only get better with the increased use of technology.
"The spirit of the game suffered while I was playing. There was a lot of acrimony in the games and when India played against Pakistan. It deteriorated to depths you cannot imagine.
"Neutral umpires have changed everything, technology has eliminated so many of the controversies and results are much fairer now. I think it should improve further with the use of [more] technology."