Barcelona coach Quique Setien is pessimistic that the Spanish top flight season will be able to be completed and has called La Liga's conditions for the campaign recommencing "a non-starter" due to the continued threat of the novel coronavirus.
La Liga has been on hold since March 10 due to the pandemic although president Javier Tebas has said matches could start up again on either May 29, June 7 or June 28, most likely without spectators.
Tebas has estimated Spanish clubs would lose around one billion euros if the season is not completed.
A draft of the league's protocol, seen by Reuters, for returning to training and matches once given the green light by health authorities recommends that clubs hold training camps at their training grounds or hotels for a two-week period before matches can start again.
Only first team players, coaching staff and a small number of other staff would be allowed to access the facility, with everyone at the training camp being subjected to two COVID-19 tests before accessing the site.
Testing would continue to take place during the camps, added the protocol.
But Setien, whose Barca side held a two-point lead over Real Madrid at the top of the standings when the campaign was indefinitely postponed, does not think it is so simple.
"Everyone wants to be ready for when the season starts again but that cannot happen until the health authorities can guarantee that there will be no problems," Setien told Catalan radio station RAC1 on Thursday.
"I have read the protocol and the reality is I don't know if it can be carried out as it is written, I think it's unworkable, I think it's very difficult logistically."
Barca midfielder Sergio Busquets also expressed doubts about the feasability of clubs holding training camps.
"We can start training again little by little but it will be difficult once everyone comes together and the competition starts again and teams start travelling," he told Spanish radio stations Onda Cero and Cadena Cope.
"I have heard that La Liga wants teams to concentrate for a few months, I think that's too much and it cannot be done. There will be too many problems."
La Liga declined to comment on Setien and Busquets' comments although a source close to the matter said stakeholders were continuing to discuss a plan to return to matches along with the association of European leagues.
"The objective of La Liga is to create a protocol of the highest possible standard that can allow return to training and get us in a good, healthy, way to the light at the end of this dark tunnel," added the source.
More than 19,000 people have died from the coronavirus in Spain although this week the government loosened the terms of a strict lockdown to allow some businesses back to work.