Rangers star Glen Kamara will be called for cross-examination as Ondrej Kudela's hearing at the Court of Arbitration for Sport is delayed until April.
The Slavia Prague defender was found guilty of racially abusing the Finland international in the second leg of the Europa League tie between the two sides in 2021.
A UEFA investigation found that he had called the Rangers man a "f*****g monkey" and Kudela was hit with a 10 game ban.
That caused him to miss Euro 2020, with the Czech international seeing an appeal thrown out by the governing body.
The centre-back has taken his case all the way to the CAS in Lausanne, with a hearing due to be held on Thursday.
But that has now been pushed back until April as the court wants to call Kamara for cross-examination.
Kudela's legal representative, Rene Ciencial, said: "Due to anti-pandemic measures, CAS only offered online negotiations on the original date of January 21, or postponement.
"Given that several witnesses have been called in, including Glen Kamara whom we want to cross-examine where an immediate response is important, we feel we would not get that with online conditions.
"We agreed with UEFA that we are not interested in doing this online and so it has been postponed until April.
"Usually, the appeal process is faster in sports arbitration, but that's not been the case this time. However, my client will exercise his right to a fair trial at CAS, in which he wants to clear his name of accusations of racism which are, according to him, completely unfounded."
Kudela appealed UEFA's decision which caused him to miss Euro 2020 immediately, but it was thrown out by their Controls, Ethics and Disciplinary Body which took in verbal instead of previous written evidence.
As well as Kudela's ban, Kamara was suspended for three games and Rangers striker Kemar Roofe was also banned for four matches too, after Slavia keeper Ondrej Kolar suffered a fractured skull in a challenge during the game, with the Ibrox club fined 9,000 euros for failing to control their players.
