The 24-year-old could pull on the famous white shirt for the first time at the Tallaght Stadium when Real travel to Kildare for a ten-day training programme starting on July 13.
They will play one friendly in Ireland - expected to be against part-timers Shamrock who currently sit fourth in the Irish Premier Division and their new Tallaght Stadium holds just 3,500 fans.
But chairman Jonathan Roche said it will be extended to hold 10,000 if the match goes ahead.
"If the match is confirmed, we will push for each team to play all 11 substitutes - and I want to be one of them," Roche said. "Ronaldo is a spectacularly gifted player and it would be a great honour for the club if he makes his debut here."
Irish sports management company Platimun One has been appointed as Real's official 2009/10 pre-season partner in the last few weeks, and confirmed one friendly would be played in Ireland.
A spokesman said: "Within the past few weeks negotiations for the ten-day visit of the world´s biggest football club were concluded in Madrid.
"The pre-season programme, which will involve the full senior squad under new first team coach Manuel Pellegrini, will take place at Carton House, Maynooth, Co Kildare, from 13 to 22 July." An announcement confirming the the match is expected next week.
This week Rovers midfielder Stephen Rice revealed manager Michael O´Neill has been running the team into the ground in preparation for the possible friendly.
He said: "I don´t think it´s been confirmed yet, but if it goes ahead it´s going to be something special.
"This place (Tallaght Stadium) would be packed to the rafters. You would have the best players in the world."
While Ronaldo is expected to earn around £154,000-a-week with Madrid, Shamrock Rovers' wage bill for the entire 22-man squad is just £12,800-a-week.
Their star player Gary Twigg, 24, has scored 13 goals in 15 matches this year. He is one of the only full-time professionals and earns £850-a-week during the season.
Shamrock Rovers, who have won the Football Association of Ireland Cup a record 24 times, used to be known as the Irish Manchester United but fell on hard times after they sold their ground in 1987.
In 1957 they drew Manchester United in the preliminary round of the European Cup, losing 6-0 at home and then losing 3-2 away.