MILAN, Italy - AC Milan made Real Madrid an offer for Ronaldo, a move that would return the Brazilian soccer star to the city where he spent five years with rival Inter Milan.

Ronaldo has six days remaining in the January transfer window to switch teams. Otherwise, he will have to stay at Madrid at least until the end of the season. Ronaldo joined Madrid in 2002, winning the Spanish league at the end of his first season - his last major title.

Brazilian soccer star Ronaldo waves to supporters as he arrives at the San Siro stadium to watch AC Milan's Italian Cup semi-final against AS Roma, January 25, 2007 in Milan. Spanish media reported AC Milan had made a six million-euro ($7.79 million) offer for the three-times FIFA World Player of the Year. [Reuters]

"We are sending an offer for Ronaldo. We are shopping so we'll see," Milan vice president Adriano Galliani said Thursday while waiting at Milan's Linate airport for the striker. "Everything of course will be down to a medical (exam), so we have plenty to do yet."

He said Ronaldo will undergo a physical Friday. Ronaldo left the Spanish capital by private jet and attended Milan's Italian Cup first-leg semifinal against AS Roma at San Siro on Thursday night.

"I want to publicly thank (Real) president Ramon Calderon for having offered us this possibility," Galliani said. "I have a meeting (in Madrid) on Monday and if all goes well as I hope, Ronaldo will become a Milan player."

The 30-year-old forward hasn't been selected to play for Madrid since the Jan. 7 defeat at Deportivo La Coruna. He said Monday his difficulties with coach Fabio Capello seem set to force him from the club.

The Spanish news agency Efe said Ronaldo was at Madrid's training Thursday, adding he did not bid his teammates farewell or collect his belongings. Efe did report that Ronaldo sent a text message to Galliani on Wednesday.

"I'll arrive, pass the medical and go to the stadium with my new president," Efe quoted him as saying.

Galliani and Madrid official Franco Baldini reached an oral agreement for Ronaldo late Wednesday for about $9.1 million, the Italian news agency ANSA reported.

Baldini did not divulge financial details of the agreement but said that it's a "long way from the ($10.2 million) that Real is asking to release Ronaldo," ANSA added. The Spanish daily El Mundo cited a figure closer to $7.8 million.