However, it is expected to be a precautionary measure only and the Portuguese star should take his place in United's starting line-up against Barcelona.
Ronaldo missed the start of this season having undergone ankle surgery after Euro 2008, and was also seen sporting heavy strapping to his ankle prior to Portugal's 2010 World Cup qualifer with Sweden in March.
Barcelona were also handed an injury worry ahead of the Rome showpiece, with defensive midfielder Sergi Busquets - who will deputise for makeshift central defender Yaya Toure - also needing treatment to an ankle in training.
Pep Guardiola's outfit continue to have doubts over the fitness of star duo Andres Iniesta and Thierry Henry, although both partook in training on Tuesday evening and are likely to start.
NEWS: Carrick confident of conquering CatalansNEWS: Sheringham tips Reds to reign in Rome
NEWS: Henry and Iniesta train ahead of final
NEWS: Evra - Marking Messi will be easy peasy
NEWS: Messi - Classy Catalans deserve to win in Rome
NEWS: Rijkaard: United have got no chance
NEWS: Rio's Rome hopes hinge on Hull
NEWS: Henry and Iniesta on course for final
NEWS: O'Shea coy on Rome start speculation
NEWS: Ferguson anticipating fantastic final
NEWS: Foreign Office advice for fans heading to Rome
NEWS: All white on the night for Reds in Rome
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