The skilful Argentine has found life up and down on Teesside since his move from Sunderland in July 2006 and has been in and out of the team.
But Arca's neat passing style fits nicely in to Mowbray's style of play and he has enjoyed something of a renaissance in the last couple of months.
His improved fortunes are best highlighted by his clever pass for Leroy Lita's second goal at Preston on Tuesday, which arrived 17 days after Arca struck the winner against Cardiff at the Riverside Stadium.
The 29-year-old knows, however, his spell on Teesside is heading for its final chapter. If he is not sold in the January transfer window, he is unlikely to be offered the Premier League wages he has been earning on Teesside when his contract expires in June.
"The club are not in the financial position they would like to be," said Arca. "They might need to sell players to get some money back. I am sure if he can move players on then the manager will try to bring in a few more to make the team stronger.
"It will be a complicated month for everyone, especially when the team is starting to play well again, but that's football. We just have to concentrate on trying to win games. That's all we can do."
He added: "I like the manager's philosophy of playing football. He likes to keep the ball and that's the way I love to play. I could not ask for a better guy to come in because that is my style.
"It's hard in this league but if you have a manager like him who can get his ideas across you can soon tick. That can make a difference. We could always have played more football than what we had been doing."
While Gordon Strachan showed a reluctance to play Arca, there is no such problem for Mowbray, who would actually prefer to keep the South American for the long term.
But the Middlesbrough manager, who will be forced to listen to offers for all of his players this month, admits Arca is just as likely to be sold as any other member of his squad.
Mowbray said: "Julio earns Premier League money. He has been there all of his career. I have spoken to him and I am in no rush to lose high quality footballers.
"But high quality footballers are really hurting us financially at the moment. Julio knows we can't continue along the lines we are going. If we get in a bid for Julio then he will have to go."
There has been a lot of talk centred on the futures of David Wheater, Gary O'Neil and Kris Boyd in recent weeks, but Mowbray feels there is likely to be increased interest in Arca in the coming weeks.
"Julio is a top player. If people are watching Middlesbrough, people might talk about David Wheater, but Julio is a top footballer," said Mowbray.
"He has developed from a full-back who used to burst down the line with Sunderland, he is now a different footballer. He is someone who can slow a game down and hit a killer pass. He is a nice guy, a good guy too.
"He is arguably our most creative player at the moment. Maybe playing in the gym because of the bad weather has helped because he is a hell of a five-a-side player. Maybe his confidence has come back from that."
Arca returns to Elland Road today for the first time since helping Sunderland defeat Leeds United in August eight years ago. Back then the Whites were chasing European dreams, so things have changed considerably at both Middlesbrough and Leeds.
Arca said: "Leeds have been down to League One, then back up again. Now they are doing really well. It's a nice place to go and they are doing well, it should be a good atmosphere.
"Nobody expected them to be joint second top. They touched rock bottom in League One but they have found away to work it out. In the Championship nobody expected them to do as well as they are."
Source: Northern Echo
Source: Northern Echo