PONTIAC (Michigan) (AFP) Brazilian Ronaldinho and star Italian midfielder Andrea Pirlo are among four top AC Milan players who will not make the trip to suburban Detroit for a Friday friendly against Greek outfit Panathinaikos. Ronaldinho suffered a strained left hamstring last week, prompting the Italian side to leave the 2004 and 2005 FIFA Player of the Year at home to recover. Remaining in their homeland were AC Milan forward Filippo Inzaghi and top midfielders Pirlo and Massimo Ambrosini. US defender Oguchi Onyewu, a standout for the Americans at the 2006 and 2010 World Cups, will be on the field for AC Milan against the Greek side at a domed stadium which was used as a venue for the 1994 World Cup. AC Milan will have tuneup matches against Juventus and Barcelona later this month before opening their Serie A campaign on August 29 against Lecce.