UEFA are waiting to receive the report of the match delegate and security officer before deciding whether to take action against what Bolton saw as the "overzealous and disproportionate" mistreatment of their fans by Spanish police.
Wanderers have lodged a complaint with European football's governing body after their fans came in for some rough treatment from police during and after Thursday night's UEFA Cup last 32 second leg against Atletico Madrid.
Spanish police said on Friday the problems at the match were "just the usual at any football game" and refused to respond to Bolton's allegations.
UEFA are not yet able to respond to the complaint until they receive all the relevant reports, which may not reach their headquarters in Nyon, Switzerland, until early next week.
Greater Manchester Police, whose Chief Superintendent David Lea was in the Vicente Calderon stadium to witness the Spanish police's behaviour, insist Bolton fans were not at fault and pledged to help the club compile a report to UEFA.
This is not the first time this season complaints have been made about Spanish police at the same venue, with Aberdeen writing to UEFA in November after they felt their fans were mistreated during their group game against Atletico.
UEFA said on Friday they were still investigating the circumstances surrounding that complaint and had not yet decided whether to open disciplinary proceedings.