Barcelona manager Quique Setien has said the introduction of five substitutes will work against his side when La Liga resumes in June, three months after it was suspended due to the coronavirus pandemic.
The temporary increase from three changes, announced by football's lawmakers the International Football Association Board [IFAB] earlier in May, will be active in all competitions which start and finish before the end of 2020.
FIFA proposed the amendment to ensure the restart of football was easier on players, with a number of matches in a short space of time expected to take its toll on them after months of inactivity.
"I think having five substitutes could actually be detrimental to us because of the way we play," Barca coach Setien told the Las Palmas Football Federation.
"We know that a lot of the time we resolve matches in the latter stages of the game. Therefore, if you give the opposition the option of putting on fresh players during that time, the weakness that is generated, by tiring their players, won't happen to the same degree.
"That said, it can also give you more resources at a specific moment. So, it is an unknown quantity and we'll see how it goes."
While teams will be permitted more substitutions, to reduce disruption in matches, each side will have a maximum of three opportunities to make their changes -- not including half-time.
La Liga will resume on June 11 with the Seville derby between Real Betis and Sevilla. Barcelona's first game back will be away at Mallorca, with a league source having told ESPN the fixture is likely to be played on June 15.
Teams in Spain are training in groups of up to 14 and will progress to full training from Monday. Setien said he would have liked teams to be given longer to prepare and hopes the rushed restart date doesn't lead to injuries.
"We thought we would have more time together as a group, but it's not to be," he added. "We haven't even been able to be in the same room to do some video analysis.
"And now, in two weeks' time, La Liga is restarting. We would have liked more time. I hope there are not many injuries and that it's not as damaging as we imagine.
"It is clear that we will start to compete with a high level of stress because you are playing for the La Liga [title] in 11 games. We do not know how that, along with the physical effort, is going to affect us. We will see as time goes by."
Barca were two points clear of Real Madrid when the league was halted with 11 games to be played. La Liga president Javier Tebas has said the plan is for all games to be completed before July 20, with Sept. 12 pencilled in as the start date for the 2020-21 campaign.