Atletico Madrid coach Diego Simeone has confirmed striker Radamel Falcao will be sidelined for "around 20 days" after suffering a hamstring injury during his side's 2-0 win over Levante on Sunday.
Falcao, 26, pulled up sore after sprinting for the ball in the 57th minute and was immediately substituted, raising concerns for the home fans.
Although the Colombia international will undergo further treatment on Monday to assess the severity of his injury, Simeone believes Atletico may have to do without their top scorer for up to three weeks.
"We don't know exactly what he has, but he is hurt. He will rest and that will serve him well,'' Simeone said. "Falcao will be a great reinforcement for us when he comes back.''
Falcao's 18 goals in the league this season have helped Atletico move within eight points of leaders Barcelona, but the performance of striker Adrian - who netted the opener for the hosts - will give Simeone some relief in the absence of his injured star.
"Adrian is important to us," Simeone said. "Everyone knows what I think of him and he needs to prove he can do it on the field. We need his game and his level because he is a player in the final metres who can do some real damage.
"We played a very intelligent game; tried to win without rushing spaces and did well down the wings. We have worked the ball through the thirds and that has allowed us to reach the opponents' area with more people."
Falco is likely to miss Thursday's Copa del Rey clash with Real Betis, as well as league matches against Athletic Bilbao and Betis.