why is this the only card not graded?

I was looking to pick up this Garnett raw off of ebay. It makes me kind of nervous that the seller has over a dozen other cards up for sale and everyone is psa graded except this one. Is their anything that I should visually be aware of that I’m missing or am I just being paranoid?
Garnett auction

Garnett auction

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Comments
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There is always a reason.
And, that is reason enough to run away from such sellers.
Seriously though, his only negatives are for slow shipping ... no prior trimming accusations etc.
Go for it!
Using the words Nervous & Paranoid in the same post isn't a good sign .... maybe you should pass on second thought!
He has 99.5% Pos. feedback and 2500+ feedback.
John
HOF SIGNED FOOTBALL RCS
I love that card.
<< <i>Is the card worth anything graded? It would cost $35 to get it graded and authenticated. >>
Authenticate what?? It's not autographed.