AC Milan have signed teenage Austrian striker Philipp Prosenik from Chelsea, the Italian club confirmed today. The 18-year-old has joined the Rossoneri on a permanent transfer for an undisclosed fee. A statement from Milan read: \"Philipp Prosenik\'s contract has been deposited with the Lega Serie A.\" Prosenik joined Chelsea in the summer of 2009 from Rapid Vienna at the age of just 16. The Austria Under-19 international is the son of former Austria international Christian Prosenik.