The US sportswear giant – which has a contract worth a reported $1bn (£768m) with Ronaldo – said it would "continue to closely monitor the situation", the Associated Press reports.
Ronaldo, 33, earlier "firmly" denied assaulting Kathryn Mayorga at a Las Vegas hotel in 2009.
Meanwhile, EA Sports told the AP: "We have seen the concerning report that details allegations against Cristiano Ronaldo.
In a separate development, Juventus – the Italian club Ronaldo joined from Real Madrid for £99.2m in July – came out in defence of its player.
The Portuguese international had previously said the allegation, first reported in German magazine Der Spiegel, was "fake news".
Ronaldo's lawyers have previously said they will sue Der Spiegel magazine over its reporting.