That is the view of the Chelsea Supporters Trust (CST) after media reports linking Mata with an exit from the Premier League club surfaced on Wednesday.
Barcelona and Real Madrid have been reportedly interested in the Spanish midfielder for some time, while it was alleged that Chelsea had offered Mata, or Brazilian David Luiz, to Manchester United in their unsuccessful bid to take Wayne Rooney away from Old Trafford.
The news took the football world by surprise given Mata's outstanding season for Chelsea last term, in which he scored 19 goals and added 35 assists in his 64 appearances in all competitions.
Chelsea released a statement that said they had not offered any players to United as part of their attempts to sign Rooney and CST spokesman David Chidgey is glad that is the case.
"I think most Chelsea supporters would be absolutely appalled at Juan Mata being offered up for a part exchange deal or looking to get him out the club," Chidgey told OMNISPORT.
"He's clearly been the best player in our team in the last two seasons and he provided the most assists in the Premier League last season.
"I think he's quite a leader in the team even though he's quite small in stature, but he leads on the pitch by example. He's bright and articulate too and he clearly loves playing for the club.
"In all honesty I cannot believe that the club would want to get rid of him.
"As for David Luiz, I know there's a few Chelsea supporters who are not enamoured with his ability to drop the odd clanger.
"But I think most do like David Luiz and I think the club love him too. There's talk of him being a future captain at the club so I can't understand why these rumours about Mata and Luiz come from because it doesn't make any sense whatsoever."
On the surface, Chelsea being open to Mata leaving the club seems bizarre, with the 25-year-old one of the best players in the Premier League last term.
But if for whatever reason, Mourinho decided to sell Mata, Chidgey believes the fans would support the decision, purely on the Portuguese's outstanding record at the club.
Mourinho never lost one of 60 home league matches at Chelsea - as part of a wider run of 151 home games without defeat - and led the club to two Premier League titles in 2004-05 and 2005-06, as they broke a 49-year drought for the crown.
Chidgey also feels that the potential sale of Mata may have nothing to do with Mourinho, and could be down to other figures at the club.
"I think most supporters are prepared to trust Jose Mourinho," he said.
"Even if he did sell Mata I think most fans would go: "let's see what happens, Mourinho is no fool he knows what he's doing".
"I can't believe he would let a player of the calibre of Mata go though, because I think he's a very smart manager. Maybe if he did go…remember it's not just Jose who makes decisions at the club.
"If Mata did go perhaps people would not point the finger at Mourinho and focus their attention elsewhere. Jose is absolutely adored at the club."