Mason said he did that in his first match against Southampton with the Carabao Cup final against Manchester City in mind – a game former Swansea player Rodon was cup-tied for – but he also did not make the matchday squad for the following two fixtures.
Dier was poor in Spurs' 3-1 defeat at Leeds last week, leading for calls for Rodon to get his place back against Wolves on Sunday and Mason has been impressed with his attitude.
Mason said: "Joe was unfortunate in terms of timing. He was cup-tied for the cup final so the first game I felt it was probably right to have the group consistent for what it was going to be in the next game.
"He's trained well, done well. All the 21 outfield players have competed in training and it's made it difficult to pick a team and a squad.
"But I've been happy with everyone, I think the defence and team has done well. So it's difficult.
"But when you play at a club like this, there's always going to be disappointed players. The most important thing for me is he's remained professional, he's worked hard, he's trained well and he's been good around the club so that's a massive tick from me."
One man who will always be picked is Harry Kane and the England captain has his sights on a third Premier League Golden Boot.
He is tied with Liverpool forward Mohamed Salah on 21 goals and Mason is backing his player to get the gong, though not at the sacrifice of the team.
"I know Harry, he is one of my best friends and I am sure he will want to win that, but he won't sacrifice it for the team," Mason added.
"Harry is an incredible player and we are so lucky to have him. If he can help us win games and also win the Golden Boot then happy days. Harry won't compromise a team result for an individual result, that's for sure."