The Belfast fighter is due to defend his title against American Miguel Jiminez on Saturday in Huddersfield.
Jiminez is a late replacement for Julio Cesar Vasquez, but last summer he went the distance with WBO champion Joe Calzaghe.
Magee, though, has been told he needs a major improvement if he wants to hang on to his title.
"
This is a fight that can take Brian
to another level
"
Barry Hearn
It was a lethargic Magee who featured in a dour struggle with American Jose Spearman in November, a fight that did not impress Hearn.
"This is a very important night for Brian,'' said Hearn. ''His career is really at a crossroads now.
"Jiminez gave Calzaghe a tough fight and this is a fight that can take Brian to another level.
''Hopefully it will set him on the path towards a fight with the likes of Robin Reid, David Starie and eventually Calzaghe.
"Brian disappointed the last time but there were a few changes of opponents.
''This is another substitute but he needs people to sit up and take notice and then we can start thinking about some really big fights.
Main fight
"The super-middleweight scene is wide open and I believe Brian has the hunger and the skill to make a big impact.
"He has a big chance on Saturday to start doing that against Jiminez who has only had two defeats in 20 fights."
The main fight at Huddersfield Sports Centre features James Hare defending his Commonwealth welterweight title against Frans Hantindi.
Also on the undercard is Dale Robinson who challenges Spencer Matsangura for the vacant Commonwealth flyweight title.