The 24-year-old, that can play as a defender, midfielder or striker, damaged his arm during the first half of Scotland’s Euro 2020 qualifying win over San Marino.
He may have surgery on Monday.
“He should be outside before pre-season – a big blow,” stated Cardiff director Neil Warnock.
“It is no good saying it isn’t a blow off. Contrary to what was said before the Scottish game [3-0 loss in Kazakhstan]I never said anything to Alex [McLeish, Scotland’s manager] about him not playing on the plastic throw.
“However he had this kind of bad [previous] injury with his kneeI presume they talked between themselves. The second game [against San Marino] was a disaster for us, but it’s one of those ideas.”
Cardiff have previously lost centre-back Sol Bamba to the remainder of the effort after the Ivorian damaged knee ligaments in the defeat at Wolves earlier this season.
Warnock also revealed the Bluebirds will be without another defender, Matt Connolly, but he has only made one appearance in 2013.
“Connolly was only coming back to training and he dislocated his arm,” the Bluebirds boss said.
“Sol Bamba’s surgery was profitable and the physician is thrilled about this. Sol is in Barcelona at the moment, recovering well.”
A blend of their game against Brighton being rescheduled and global fixtures mean Cardiff have not played as their 2-0 triumph over West Ham on 9 March.
They come back to action using a chilling double-header, using a home game against Chelsea on Sunday followed by a trip to Premier League champions Manchester City on Wednesday.
The two games might have a significant bearing on the Bluebirds’ hopes of avoiding relegation, as they’re two points adrift of safety.
Warnock is worried with the game fitness of Iceland midfielder Aron Gunnarsson, who has been hampered with injuries this season and is some one who the Cardiff director had expected could have some sort of rest during the global period.
But the 29-year-old, that will join Qatari side AlArabi in the summer, played 63 minutes of Iceland’s Euro 2020 qualifying win in Andorra after which a whole 90 minutes of a 4-0 defeat in France.
“With Iceland I had been disappointed. I had been originally told Aron was not going to play with on the plastic throw to its first game afterward he played with over one hourand then he plays 93 minutes against France,” said Warnock.
“I can not know that in all. I am aware that it’s really a new manager and also you also would like to excel, but when you’re 3-0 down, clearly you may substitute a person?
“I bent over backward for Iceland last season to let him really go the worldcup and he had three months in 2013 if he had been outside and then we had to create up him. I was disappointed with an Iceland manager and I will be speaking to him.
“That doesn’t matter today as Aron is leaving at the end of the season.
“But we’ve been handling himhe’s not played with two games and most of a sudden we have Chelsea and Man City in the distance of three days.
“I simply thought it had been pure selfishness and I am so disappointed in Iceland for doing this.”