The Seattle Sounders lost Osvaldo Alonso and Roman Torres to injury in the team's 3-0 win over the Vancouver Whitecaps on Wednesday.
Midfielder Alonso and center-back Torres were subbed off in the second half of the match.
Alonso has been diagnosed with a quadriceps strain, while Torres is believed to have a knee or groin problem.
"They're tough kids," Seattle coach Brian Schmetzer said after the match. "It'll be day-to-day on Roman.
"Ozzie has a strained quad, but what he proved last year is that he'll come back and he'll feature for us in the last couple games."
The Sounders, currently fourth in the Western Conference, have just three games remaining before the playoffs begin.