After yet another turbulent week in south Wales, and on the eve of a crucial relegation battle against Fulham, it has emerged that Vincent Tan's son, Morvin, is working for Cardiff City in an unofficial capacity, including being involved in incoming and outgoing transfers during the January window.

The Guardian has learned that Morvin, a student in London, has been acting as a conduit between his father and the Premier League club, primarily by "taking a look at the numbers" at Cardiff in relation to player transactions. Morvin is not involved with the identification of players and sources at the club have stressed that he has the power to sign off a deal only once it has been approved by his father, after already going through various checks at board level.

While there is no suggestion that Morvin is doing anything improper the fact that he has any part to play in player transfers at Cardiff – he is in his early 20s and has no previous experience of working in professional football, let alone at the highest level – will raise eyebrows.

Part of the thinking behind Morvin becoming involved appears to be that his presence provides his father, who owns Cardiff, with another set of eyes and ears at the club as well as providing a further check on finances. Morvin is not, and has never been, on the payroll, unlike his friend Alisher Apsalyamov, the 23-year-old Kazakh who replaced Iain Moody as head of recruitment in October before being forced to leave the UK after his visa application was rejected.

It is understood that Morvin has formed a close working relationship with Will Salthouse, the agent who represents both Wilfried Zaha, who joined Cardiff on loan from Manchester United in January, and Kenwyne Jones, who arrived as part of a swap that saw Peter Odemwingie sign for Stoke City.

The latest development comes after the news that Vincent Tan offered the Cardiff players an illegal bonus if they avoid relegation. The Premier League have asked Cardiff for an explanation for the £3.7m survival bonus that Tan proposed during a meeting at the team hotel in London on Saturday night, before Sunday's game against Tottenham Hotspur, which Cardiff lost 1-0.

Ole Gunnar Solskjaer, the Cardiff manager whose weekly press conferences seem to be dominated by questions about his owner, suggested there is nothing to be concerned about in relation to the bonus. "We've spoken to the Premier League and they know the situation and I don't think there will be a problem," Solskjaer said.

Solskjaer refused to criticise Tan for his actions, which breached Premier League rules. "Whether this was said or that was said [by Tan], that's missing the point for me, that's completely irrelevant. What's relevant is that we are there together," Solskjaer said, when asked about the bonus offer.

"He was there to encourage the lads, back the team, he's behind us. And we're here to get the job done. He was there to rally everyone. I invited him to come. We showed unity and that's what you've got to show to the players, that we're all in this together. He's the owner of the club, he wants to be successful, which is great, and he came there and showed that he is backing them. And he did great. When he was stood up on that chair and was talking to them: brilliant."

On the pitch the stakes could hardly be higher this afternoon. Cardiff, second from bottom in the Premier League, are at home to Fulham, who are anchored to the foot of the table. With only four points from a possible 24 under Solskjaer and the 4-0 thrashing at home against Hull City a fortnight ago, Cardiff badly need a win to revive their hopes of staying in the Premier League.

Asked what he wanted from his players against Fulham, Solskjaer said: "Courage. And to play with no fear, go out there and play as [though] you are going to win the league in this game, play like you are going to gain something, because that's what we've got to do. Go out there, be brave, get on the ball, take responsibility and, of course, have that fight in you."