Gdansk, Poland German central defender Per Mertesacker has been given the all-clear to face Portugal in their opening Euro 2012 match on Saturday after suffering an injury scare in training.

The Arsenal centre-back, who was out for three months last season following ankle surgery in February, collided with team-mate Jerome Boateng from a corner in training on Thursday, but after initial concerns, was given the all-clear.

Mertesacker comes into the European Championship with just two games under his belt having played in last month’s friendlies against Switzerland and Israel, but Germany assistant coach Hansi Flick said he is fit to play.

“There was some brief uncertainty about Per,” said Flick here before Germany flew to Lviv, Ukraine, on Friday morning for their Group B match.

“After a corner, he collided with Jerome Boateng and he remained on the ground for a while, but it wasn’t as dramatic as it first looked and he was quickly given the all-clear.”

With 81 appearances for Germany, Mertesacker — who played in the defeat by Spain in the Euro 2008 final — looks set to partner either Borussia Dortmund’s Mats Hummels or Bayern Munich’s Holger Badstuber at centre-back with captain Philipp Lahm at left-back and Jerome Boateng on the right.