Judge Pablo Llarena placed Rovira under judicial control, but stopped short of putting her behind bars for the duration of an ongoing probe into charges of rebellion, sedition and misuse of public funds.
Rovira is the deputy leader of the leftwing separatist ERC party, whose chief Oriol Junqueras has been in custody since November.
Junqueras was jailed after Madrid ousted his government and dissolved the Catalan parliament, following a failed declaration of independence on October 27th.
Catalonia's deposed president, Carles Puigdemont, travelled to Belgium where he has gone into self-imposed exile -- evading a similar fate to Junqueras and three other jailed secessionist leaders.
Rovira was questioned Monday over accusations that she participated in meetings seeking to set out a "road map" plan for Catalan independence.
Protestors demand freedom for jailed Catalan leaders outside the Supreme Court on Monday. Photo: AFP
She told the judge that she attended the meetings because Puigdemont had ordered her to, according to the source, who attended Monday's hearing.
Llarena said Rovira must post bail "within a reasonable timeframe", the source added.
Another separatist leader, Marta Pascal, was next up for questioning.