Portuguese newspaper A Bola claims the United boss is set to offer €14m for the Liverpool and Real Madrid target although Cruzeiro president Gilvan de Pinho Tavares is thought to be determined to hold out for more.
With Liverpool and Real Madrid monitoring Ribeiro, the Brazilian club feel they can extract more from Manchester United for the Campeonato Brasileiro Best Player of 2013.
Moyes is under pressure to improve the squad in the January window, and admitted earlier this week that he's keen to bring in new faces to help improve the club's standing.
The defending Premier League champions currently sit eighth in the table, eight points off Liverpool at the top.
And central midfield is an area in need of improvement for United, with Marouane Fellaini currently sidelined for six weeks with a wrist injury.
Tom Cleverley and Anderson have struggled to make a compelling case for regular inclusion in the starting eleven, leaving Moyes short of first-class options.