Calvin Johnson has shattered records, obliterated opponents' coverage schemes, and established himself as the NFL's premier receiver.
Scarily enough, his best may still be yet to come.
Appearing on "NFL AM" on Thursday, Lions quarterback Matthew Stafford said that Johnson believes he could improve going forward.
"I mean, he thinks he can, which is all that matters," Stafford said, via NFL.com. "That guy works harder than anybody I know, and he thinks he can get better, so I wouldn't put anything past him. He's a guy that can obviously run all the routes, inside, outside, make all the catches, and is a smart football player and a really good teammate."
It's inconceivable to imagine Johnson getting better. He's coming off a 2012 campaign in which he broke Jerry Rice's single season receiving yards mark -- with broken fingers, no less -- and proved not even triple coverage can contain him.
Johnson's improvement obviously would benefit the offense, but it may partially be for...