Asif was one of three Pakistan players banned by the International Cricket Council after being found guilty of fraudulently bowling no-balls - as part of a betting scam - during the Lord's Test against England in August 2010.
The 30-year-old has repeatedly denied he was part of any such plan before appealing his five-year playing ban, handed down two years ago, to the CAS on Thursday.
Salman Butt, who was Pakistan captain at the time, attended his own CAS hearing on Friday. The third player, teenage quick Mohammad Amir, has opted not to contest his suspension.
Asif's CAS hearing in Lausanne, Switzerland on Thursday lasted eight-and-a-half hours during which he appeared before a three-man tribunal headed by International Rugby Board judicial officer Graeme Mew.
A decision is due within a month and while the bowler's London-based barrister Ravi Sukul, who attended the hearing but was unable to give detail of the proceedings under a CAS order, remained optimistic he revealed his client had become anxious about his future.
Asked if Asif feared his international career could be over, he told Press Association Sport: "That would be right. Something about that came up (in the hearing). It's natural I think that he would feel this way. He wants to play cricket again."
The CAS appeal is set to be Asif's final point of appeal to his playing ban and Sukul revealed the 23-Test right-armer, a lithe figure during his playing days, had visibly lost weight in the lead up to the hearing.
"He is still fit although he has lost a bit of weight. If you see him now from how he was on the day of the Lord's Test he is a lot slimmer," he said. "I think quietly he has been worried about how this will all go. He remains, as do we, that there will be a hopeful outcome.
"Mohammad wasn't deliriously happy afterwards but he was comfortable with the way the proceedings went. He was labouring under the effects of the ban as he has been doing so for many months. It was almost two years to the day since the ICC handed down the ban."