The 23-year-old, who signed for the Magpies from Swansea City in a deal worth around £12 million during the January transfer window, have received criticism from some quarters about his performances towards the end of his spell with the Welsh club.
However, McClaren believes that Shelvey, who was dropped earlier this season after being criticised by former Swans manager Garry Monk for apparent laziness, will provide the best possible answer to those who doubt him.
The former England head coach told the Chronicle: "He has great potential. When somebody leaves the best answer for everything is what you do on the field, for Jonjo especially.
"He’ll keep quiet and just perform."
Shelvey, who scored 10 goals in 96 matches for Swansea before moving to St. James' Park last month, has been a regular under McClaren, playing in all five Premier League matches since his arrival.
The former Liverpool man and his teammates are currently on a training camp in La Manga, with the Magpies not due to play again in February.
When they return to action they will continue the struggle which faces them, with the North East club currently third-bottom of the league table, in the relegation zone on goal difference.