Vidal played an hour against Australia, then 88 minutes against Spain before being rested for their group-stage clash with the Netherlands.
The Manchester United target has declared his fitness for their round of 16 date with tournament hosts Brazil in Belo Horizonte on Saturday.
And Sampaoli said it was due to the Juventus man's courage that he was able to get himself up for their World Cup campaign, having undergone knee surgery in May.
Vidal played in the UEFA Europa League semi-final for Juve in early May before going under the knife, and Sampaoli did not blame the Serie A club for continuing to play him despite his injury.
"We as the Chilean national team believe Vidal is not even close to 100 per cent, but we agree with Juventus that Vidal has to play for many reasons: for his courage, his manliness and because he is an emblem," Sampaoli said.
"So, for what time he can play, he is doing his best to be ready.
"He did it to play against Spain, with a big effort and he is doing it daily with 1,000 treatments.
"There are a lot of reasons that make me wish Arturo could be on the pitch."
In a potential blow for Chile, midfielder Gary Medel pulled up tight from training on Thursday, with Sampaoli conceding: "We are going to see how he evolves."
Medel has played every minute for Chile in their finals campaign so far.
Chile are looking to create history against Luiz Felipe Scolari's men, as they have twice previously met Brazil at the World Cup - incidentally, each time saw them clash in the round of 16 - for heavy 3-0 (2010) and 4-1 (1998) losses.
Sampaoli said this is Chile's opportunity to show their more-fancied South American rivals what they are made of.
"Look, historically Chile has played at this stage against Brazil. It is not by chance Brazil took the win," he said.
"Brazil has won five World Cups and because of that is one of the most important expressions in football history. Therefore to beat them it is not easy for anyone.
"Statistically Brazil overcomes any other national team in any place in the world. Moreover, they play at home, with its fans supporting and with all their obligations. On top of that, Brazil's manager and players have a lot of quality.
"However, we feel we have our chances to change this history that it is very complex, so we are going to face this challenge bravely and full of conviction, as this group has demonstrated before, knowing we have a tough opponent.
"We are going to try to suffocate them with our scheme."
