The 23-year-old Sunderland winger has enjoyed a remarkable six months after emerging from the shadows under Martin O'Neill on Wearside and establishing himself as a first-team regular.
McClean's rise to prominence since his £350,000 summer move from Derry City has been little short of spectacular, and he was recognised at senior international level when he won his first cap as a substitute against the Czech Republic in February.
Manager Giovanni Trapattoni has worked hard to calm the excitement over the emerging talent, but has been impressed by what he has seen so far, as has his assistant Tardelli.
The former Italy international said: "He is a good boy. He wants to work because he knows he needs to learn many things.
"He is strong physically and I think he will be for us a good player."
Trapattoni has signalled his intention to work with the left-sided McClean on the right flank too, having seen him prosper when cutting inside for his club.
It remains to be seen how the manager will use him during the tournament in Poland and Ukraine, but asked if he still has time to win a place in the starting XI, Tardelli was noncommittal.
He said: "I don't know. He is in the squad, but we have also other players like [Damien] Duff, like [Stephen] Hunt, like [Aiden] McGeady.
"Surely, he is the future, but maybe it is possible also this time."
Trapattoni and Tardelli put their players through a light training session at a sun-drenched Gannon Park in Malahide on Monday morning.
Defender John O'Shea was rested once again as he recovers from an ankle problem, while Keith Fahey and Kevin Foley, who are nursing groin and hamstring injuries respectively, worked away from the group once again, although both are expected to join in within the next 48 hours.
Skipper Robbie Keane was expected to arrive from the United States later on Monday with his hamstring strain still one of the major topics of discussion despite repeated reassurances that it will not be an issue.
Indeed, Tardelli is confident he will be fit to play in Saturday's friendly against Bosnia-Herzegovina.
He said: "The doctor has spoken to him and with the Galaxy doctor, and he said there is no injury.
"I think he will be ready for the next match.
"Foley tomorrow or Wednesday will come with us, and Fahey maybe Tuesday. John O'Shea needed two days of rest and I think for the match, he will be ready."
Tardelli added with a smile: "Everything is good - also the weather."
Trapattoni and Tardelli are veterans of numerous campaigns as both players and coaches, with the latter famously a World Cup winner.
That experience has already proved vital in guiding the Republic into the finals, and the assistant manager acknowledges it will be important once the squad arrived in Poland with Ireland not having played on the big stage since the 2002 World Cup finals.
Only Shay Given, Damien Duff and Keane of the current squad tasted action in the Far East, with defender Richard Dunne travelling but not making an appearance.
Tardelli said: "Experience is very important for the players. We have also new players.
"Giovanni and I, we know the tournament because I was a player and was a coach in it, and Giovanni was a player and a manager in this kind of tournament.
"We will speak with the players."
However, while Tardelli is relishing what lies ahead, he admits the excitement of preparing for a major tournament as a coach does not compare to that of doing so as a player.
He said: "No, it's totally different, totally different. I preferred it as a player because I was very young.
"But it's my job and I like it."