The pair moved to West Ham from Brazilian side Corinthians in August at the prompting of Iranian businessman Kia Joorabchian, who brokered the deal and was hoping to buy the club.
But when a consortium led by Icelander Eggert Magnusson agreed to buy West Ham this week, rumours started to circulate that Tevez and Mascherano would move elsewhere during the January transfer window.
FIFA regulations, however, forbid players from signing and playing for more than two clubs during a 12-month period from July 1st to the June 30th.
Tevez and Mascherano played for Corinthians in July and August before their transfer deadline day move to West Ham, meaning they would not be permitted to sign and play for another club until next July.
A FIFA spokesman said: "Our rules say players may register for up to three clubs in that 12-month period, but may not play for more than two."
Pardew still wants the World Cup duo to succeed in the Premier League after a turbulent start to their West Ham careers.
"They're owned by the person whose takeover didn't happen, and that might be a problem," he told reporters on Thursday. "But I hope that they begin to grow here quicker than they have done in the previous period, and I think that can happen.
"Maybe the situation will work for them as well because they can settle down now and we can get the best out of them."