The 21-year-old reportedly refused to take part in a session with his team-mates on Tuesday, preferring to work out in the gym on his own.
That decision was attributed to Tottenham's interest in the Colombian, who is believed to be keen to be allowed to speak with the Londoners.
Ajax have so far stood firm over the player, rejecting Spurs' opening offer of £28m as they demand closer to £40m and offering the player a new deal after just one season at the club.
Spurs are said to have sent a delegation to Holland to thrash out a deal but Sanchez's participation in training on Wednesday would suggest that no agreement is imminent.
The youngster was left out of Ajax's squad for their opening game of the season on Saturday after telling coaches that he was not in the right frame of mind to play.
Despite that, the player could be seen smiling away as he trained with his team-mates on Wednesday. Could Spurs be set for another transfer blow?