Barcelona assistant coach Jordi Roura has acknowledged that the likely absence of Lionel Messi for the Champions League second leg against Paris Saint-Germain represents a major blow.
Barca were held 2-2 in the quarter-final first leg at the Parc des Princes on Tuesday night, with Messi - the scorer of the opening goal - and Mascherano both having to be substituted.
Messi, who came off at half-time, is expected to be out for around three weeks after sustaining a leg injury, but Roura was awaiting the results of Wednesday's scans before ruling him out of next week's return match.
"Messi has a small problem and we don't know how it will affect him until he undergoes the tests tomorrow," Roura said.
He added that, should Messi be unavailable for the return leg, it "will be a major loss because he is the best player in the world, but we have a big squad, and good players, and will try to win the tie".
Mascherano will be suspended for the return leg at the Camp Nou having picked up a booking in Paris and is expected to be sidelined for between four and six weeks with a knee problem.
With Carles Puyol also set to miss out after undergoing knee surgery last month, Roura said that Gerard Pique would "obviously become more important considering we are losing numbers in defence".
He added: "If we end up not having Leo or Mascherano in the return game, that will be negative because they are very important to us, but we will try to make use of our large squad."