Tottenham captain Cristian Romero is a "leader" but must learn to control his aggression after his second sending-off of the season, manager Thomas Frank says.

Romero was shown his latest red card for a tackle on midfielder Casemiro in Saturday's 2-0 loss at Manchester United, meaning he will be suspended for four games.

Speaking at a press conference as Spurs prepare to take on Newcastle United on Tuesday, Frank said he was confident the 27-year-old Argentina centre-back had the right blend of skills to succeed.

"For me, I think he is a leader. He is a young leader. He's learning every day.

"I've said I used the example when I was 30 years old. I thought I was on top of the world, but I was no way near the level I am today in terms of leadership and understanding things.

"And then when you have a player that's playing with so much passion and aggression, things like that can happen.

"That's not to say he shouldn't learn from it, of course, he needs to learn from it, going forward."

Frank had already defended Romero after Saturday's match, saying he would not consider taking the captain's armband away from him.

He will not feature again domestically until 15 March when Spurs take on Liverpool.

Also missing for the next four to five weeks will be defender Destiny Udogie, with Frank confirming the 23-year-old Italian has sustained hamstring damage.

His absence adds to Tottenham's injury woes, with only 11 fit senior players available for their game against Manchester City at the start of this month.

Asked whether Dejan Kulusevski, who has been out with a knee injury since May, is likely to play this season, Frank said: "I don't know.

"[He] has got another appointment at the end of this week where we will know more, but of course if he's out of the Champions League squad it's a sign it is not tomorrow [that he will return]."

Following a seven-game winless run in the Premier League, Spurs are 15th in the table, six points above the drop zone.

Asked if he viewed the club as being in a relegation fight, Frank told reporters there was "no doubt we are desperate to win games, desperate".

"Of course, we haven't won enough," he said. "If you are not desperate, you do not understand the situation you are in."