Catalonia's parliament is set to choose its next president later on Tuesday, but the official candidate Carles Puigdemont remains in Belgium, at least for now.
Spain's constitutional court said on Saturday that the fugitive politician must appear in person at the plenary session if he wants to be sworn in as regional leader.
Puigdemont's lawyer has refused to rule out a surprise appearance in the Catalan assembly, even though the ousted politician faces almost certain arrest on charges of rebellion and sedition if he returns to Spain.
Catalan speaker Roger Torrent faces several difficult choices. He could allow a vote in parliament with either Puigdemont present or joined via video link, defying Madrid and the constitutional court. The tribunal ruled that the ex-Catalan president cannot govern from abroad.
Another option for Torrent would be to seek a different candidate for Catalan president, though that would likely risk a backlash from the pro-independence movement.