Legia Warsaw Champions League appeal set for Monday
Legia Warsaw's Polish defender Bartosz Bereszynski (L) vies for the ball with Trabzonspor's midfielder Olcan Adin during a match on Novemver 7, 2013 in Warsaw - by Janek Skarzynski
Polish side Legia had mauled Celtic 4-1 in the first leg of their third qualifying round tie in Warsaw, and beaten them 2-0 in the second leg.
But the Poles were booted out of the competition by UEFA for fielding an ineligible player in Edinburgh.
They then failed in an appeal to UEFA overturn the exclusion, but CAS on Friday confirmed that Legia had lodged a further appeal.
"A decision...is likely to be issued on Monday 18 August around 18:00 (Swiss time/1600GMT)," said a statement from the Lausanne-based arbitration body.
The sanction on the Poles related to Legia's decision to play defender Bartosz Bereszynski for the last four minutes of the second leg in Edinburgh.
Bereszynski had been sent off in Legia's concluding Europa League match last season.
He was suspended for violent conduct for the club's two matches against Ireland's St Patrick's in the second qualifying round and also missed the first-leg victory over Celtic.
But it then emerged that Bereszynski had not been registered in Legia's squad for the second qualifying round, meaning the matches did not count towards his suspension.
Legia argued that there had been a huge misunderstanding, and that applying the letter of the law was harsh and unsporting.
A CAS decision will have to be made quickly as Celtic are due to face Slovenian side Maribor in the Champions League play-offs on Wednesday.