* Tests show a thigh muscle strain not a tear
* May be able play in second leg against Barca
* Playmaker Arda Turan sustains a groin injury (Adds Arda Turan injury)
MADRID, April 2 (Reuters) - Atletico Madrid top scorer Diego Costa has strained and not torn a thigh muscle, the La Liga club said on Wednesday, suggesting the Brazil-born forward will not be sidelined for as long as feared.
Costa was forced off after 30 minutes of Tuesday's Champions League quarter-final, first leg at Barcelona, which ended 1-1, when he pulled up clutching the back of his leg.
Atletico said on their Twitter feed tests had revealed a muscle strain instead of a tear. The club did not specify how long he might be out of action but local media suggested he might be available for the return leg at the Calderon next Wednesday.
Atletico said on their website (www.clubatleticodemadrid.com) later on Wednesday separate tests had shown their Turkey playmaker Arda Turan had a groin injury that required "physiotherapy and recuperation". They did not say how long he might be out.
Costa had scored seven goals in five appearances in this season's Champions League before Tuesday and has 25 in 30 La Liga outings.
Atletico coach Diego Simeone told a news conference after the match at the Nou Camp that Raul Garcia, David Villa or Adrian were ready to stand in for the Spain international. (Reporting by Iain Rogers, editing by Pritha Sarkar)