Maddison, 19, is held in high regard by many Premier League clubs, with The Times describing him earlier in the month as the 'new Dele Alli'.
Newcastle face serious competition from Tottenham, who also had a scout at Coventry's 1-1 draw with Walsall, even sending head of recruitment Paul Mitchell along too.
Maddison is an attacking midfielder, who The Independent reported late last year was attracting interest from both Liverpool and Arsenal.
Given the way Dele Alli has quickly acclimatised to the Premier League, and the multiple clubs who have expressed regret at missing out on the England international, teams may not want to hang around and get beaten to Maddison.
With Coventry battling for promotion to League One, currently in the play-off spots, Newcastle may find they are more successful bidding if they agree to loan him back to the Sky Blues until the end of the season.