The phrase "great defender" refers to a person or thing that protects or defends very well. It suggests someone who is skilled at ensuring safety or shielding others from harm. Full definition
The way we live today wages a constant battle on one of our body's greatest defenders of our health — our immune system. (parsleyhealth.com)
This is why sanchez and ozil will run away from this club, our defense is so poor but we are going for an injury prone good but not great defender. (justarsenal.com)
However, he's made ten appearances this season and proved that he could be the club's next great defender — which is definitely worth more than 60. (caughtoffside.com)