While Boothroyd admits that Maddison is one of the players Gareth Southgate is monitoring for the coming weeks and months, he does not believe the player is ready just yet.
Maddison recently joined Leicester City and has put in some impressive performances in the Premier League.
"I don't think he is ready for the senior team yet," Boothroyd told Sky Sports.
"But he certainly has got a lot of qualities.
"He is very creative and he's done really, really well for us.
"He's a late developer, if you look at his pathway he's played in Scotland, League Two, League One, the Championship and now the Premier League.
"He's done the steps and got the games under his belt. He is on our radar in the U21s and he's on the seniors' radar."