Thanks to all who responded.
The piece in question was a zero clearance insert for my table saw.
I bought some 1/2 MDF, traced the original insert and routed the MDF with a pattern bit. Came out nice.
When I put it in the saw, I noticed that it stuck up above the table. Knowing that I needed to cut out where the saw has supports, I did that with a forsner bit. Still stuck. I found that my saw has a bit of a manufacturing "flaw". There is a slight lip on the bottom of the blade cutout that is not even with the top. I figured that I just needed to take out about 1/8 of an inch at these points I'd be happy. Hence my post.
What I did - I have a drum sander and all I needed to do was to slightly sand the edges where the MDF was catching. I did and it now fits fine!
I will be making more of these, so thanks for the tips about resawing. I think that might work. I also think if I just routed a rabbet around the outer edges that probably would work as well.
Again, thanks to all who helped me.
MJ