"Today's medical was positive so that mean's he can join us [in Austria] on Sunday. I am pleased because he is used to playing under big pressure, he is intelligent and we got him at the right price.
"If you look at the side we had out against Austria Vienna, add the French players who are not back yet and then Lehmann, we are competitive again."
Lehmann said: "I am delighted to be joining Arsenal. They are one of Europe's great clubs and they have many fantastic players. Hopefully I will impress the Club and its supporters and I'm also very much looking forward to playing in the English Premier League."