Mourinho was pictured training with Tanguy Ndombele on Hadley Common, while Davinson Sanchez and Ryan Sessegnon were seen running side by side.
Brazilian football great Ronaldinho and his brother were jailed almost exactly a month ago to await trial on charges of using false passports to enter Paraguay.
The decision would keep the Dutch league in line with UEFA, which has warned teams risk exclusion from the next Champions League if their domestic competitions are ended prematurely.
The German Football League is in discussions with the clubs and authorities about the top two leagues resuming at the start of May, with a decision expected on April 17.
Premier League and England's three other professional divisions are all suspended indefinitely because of the COVID-19 outbreak.
England's wealthy top-flight stars have come under fire over their lack of action, with British Health Secretary Matt Hancock calling for them to take a cut and "play their part".
He said the decision was "not linked to any bribes, we categorically deny this."
The COVID-19 pandemic has killed nearly 14,000 people in Spain, the world's second hardest-hit country after Italy in terms of deaths.
FIFA has urged players and clubs to reach agreement over wage reductions and players are reportedly set to start negotiations on a club-by-club basis.
The new deal comes after he worked his way back into the team under coach Hansi Flick after being frozen out by previous coach Niko Kovac.
In an interview published on Friday, Carlo Ancelotti, the veteran Italian manager, now in charge at Everton, emphasised that point.
Players' salaries will be reduced by a third of their gross annual earnings if the season should be cancelled, and a sixth if it resumes.
On the international stage, Antic led his native Serbia to the 2010 World Cup, where his team beat Germany 1-0 in the group stage but failed to advance to the knockout rounds.
Jurgen Klopp's Liverpool appeared set to secure a first English top-flight title in 30 years when the season was suspended, sitting 25 points clear of second-placed Manchester City.
Mehdi Benatia, Almoez Ali, Ali Afif, Mohamed Musa, Ismail Mohamed, Amine Lecomte and Mohammed Muntari were all part of the campaign.