Mason joined the Reebok Stadium earlier in the summer and his performance last night suggested that it was an error from Cardiff in allowing him to go out on loan.
The Bluebirds spent big money on a range of attacking additions over the summer, but whilst they failed to hit the back of the net against Middlesbrough, Mason found it all too easy.
The diminutive forward bagged a hat-trick against Rotherham United allowing his side to grab a vital three points against Rotherham United.
It added further pressure on Ole Gunnar Solksjaer who has been tasked with guiding his side to promotion this season, after they dropped out of the Premier League last year.
Cardiff invested heavily and have created a strong squad for a second tier side, but their start to the season has been average at best.
They currently occupy 17th spot in the table and their 1-0 defeat against Middlesbrough was their second home loss in the space of four days, after Norwich triumphed at the Cardiff City Stadium on Saturday.
It has piled the pressure on the side and Mason's performance has only gone to add insult to injury in what was a very frustrating Tuesday night for the club.
Here is some of the best reaction from Cardiff fans, on social media site Twitter, to Mason's excellent performance for Bolton.
Solskjaer knows what he's doing letting Mason go and bringing Macheda in! :------) #CCFC— Craig Hopkins (@craigs_house) September 16, 2014
Joe mason scores a hat trick for Bolton and city lose at home to borough. Well done ole. You're a footballing genius ball #ccfc— Jordan Gibbs (@gibbomay3) September 16, 2014
Joe Mason scored a hattrick tonight, why are we even sending him out on loan— CAI (@ccfc_cs) September 16, 2014
We have loaned mason out for 2 seasons now, we could do with his clinical finishes to be honest!— Conor Smith (@smithy_ccfc) September 14, 2014
Cardiff city can barely get a shot on target and Joe mason bags a hat-trick on loan at Bolton. Says it all really. #CardiffCityFC— Andrew Abbott (@Abzofdoom) September 17, 2014
What is Joe mason doing on loan, he's a friend of mine and was gutted he was sent out on loan when he didn't want to go.scores a hat trick— Richard Jones (@Richard12545678) September 16, 2014