Mike Tyson believes Anthony Joshua is not a finished article yet and stll has more to learn .
Tyson , 54 , is due to fight Roy Jones Jr, 51 , in an eight – round bout later on November 28 revealed that Joshua will find it difficult beating smaller boxers.
Joshua holds the WBA , IBF , WBO and IBO champion titles is poised to fight Kubrat Pulev on December 12
Also , a fight with Tyson Fury awaits him as the two British champions have agreed on finances on a two- fight deal for 2021 .
“ That guy could learn some more . He could be taught some more stuff , ” he said .
“ I don ’ t think he’ s a paper champion , I just think he’ s a big guy.
“ It ’ s hard to fight being that big it ’ s very difficult being that big and having to fight a smaller guy. ”