BARCELONA forward Alexis Sanchez has torn a thigh muscle and will be out of action for 10 to 15 days.The Chile international limped off at the end of Barca’s 3-1 home win over Sporting Gijon on Saturday after having come on as a second-half substitute, and will miss Wednesday’s Champions League last 16 second leg at home to Bayer Leverkusen."Alexis is 22, he has to develop and know what it is to play every three days,” coach Pep Guardiola told reporters. "But he is a vital player and we will miss him. It is one more hurdle to overcome.”Aside from the injury to Alexis, Guardiola said he was pleased with the way his players recovered from Gerard Pique’s sending off early in the second half to win, and picked out midfielder Seydou Keita for special praise.The Malian, starting for the first time since November, struck a curling shot into the top corner to put Barca 2-1 ahead in the 79th minute. It was his first league goal this season."He didn’t just score a goal, it was a fantastic goal,” Guardiola said.Champions Barca closed the gap on leaders Real Madrid to seven points, with Jose Mourinho’s team not playing at home to Espanyol until Sunday.