The seller appears to state the bat may have been looked over by an autograph authenticator who did not approve the signature since their letter comes with the item.

The bat has not been authenticated by a well known authentication company or authenticator. But it was examine by a impendent one. The letter in question will be sent with the bat to the winner of this auction.

I would say if the letter approved the autograph, the seller would have sold the item as such with a genuine autograph. Still a neat item for $100.00.