The former Hearts defender sustained the injury in the 2-0 European Championship qualifying win in San Marino on Sunday.
The versatile 24-year-old, who was out for ten months after a cruciate ligament knee injury in 2016, will have an operation on Monday and miss Scotland’s Euro 2020 qualifiers against Cyprus and Belgium in June.
“He’s having an operation and should be out until pre-season,” said Cardiff manager Neil Warnock, who denied reports that he had prevented Paterson from playing in Scotland’s opening Euro 2020 qualifier on a plastic pitch in Kazakhstan.
“It’s a big blow, it’s no good saying it isn’t. Contrary to what was said before the Scotland game I never spoke to him about not playing on a plastic pitch.
“But he’s had such a bad knee over the last 12 months I think they spoke between themselves. The second game was a disaster for us, but it’s one of those things.”
Meanwhile, Sheffield Wednesday manager Steve Bruce has taken a swipe at pundits who criticised Steven Fletcher over missing Scotland’s double header.
Bruce said: “I have seen all this nonsense written and spoken about him which would upset anyone. At the end of the day, he [Fletcher] had to come off in the last game [against Blackburn] so he was genuinely injured.
“I wish people would do their homework on him before writing these awful stories about him.”
Fletcher, who has scored five goals in his last six Wednesday outings, is rated “highly doubtful” by Bruce to feature against Stoke today.
l Mark Bullingham is to be the next chief executive of the Football Association.
Currently the FA’s chief commercial and football development officer, Bullingham will replace Martin Glenn, who is standing down at end of this season.