The 29-year-old forward limped off shortly after scoring in the first half of Paris's 4-0 win over Stade Rennais on Sunday, but Tabarez was hopeful of having him available for Thursday's fixture in Montevideo after initial scans proved promising.
"He felt some pain during the match he played in. It wasn't when he made the goal but some time before," Tabarez told reporters.
"There was some contact or some suggestion from the people of Paris Saint Germain to do the recovery there and the player completely refused it."
Uruguay are second, one point behind leaders Brazil, in the 10-team South American standings, where the top four sides are guaranteed a place at the 2018 World Cup in Russia.
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Tabarez, though, was wary of the challenge posed by Ecuador, who sit third in the standings and beat the Uruguayans 2-1 last year in the reverse fixture.
"It's not going to be easy, is it? In this qualifier, Ecuador got a lot of away points, more than 50 percent away (from home)."
(Reporting by Reuters TV. Editing by Patrick Johnston)
