Topps monopoly over baseball cards was starting to crumble by the late seventies. Donruss and Fleer were both starting to make headway into the hobby, but they would still need a court decision to turn in their favor.
In anticipation to the late 1980 court ruling, Donruss made prototypes for cards, so they weren't caught off guard by a quick decision.
Donruss created three different prototypes. One of Reggie Jackson, one of George Brett and one of a blank card.
As you can see, this design is in line with the first official baseball sets from Donruss. There are bright primary colors and lots of precise lines. Donruss took so much care in this prototype, that the pictures look better than some of the pictures actually used in the 1981 set.
In fact, Donruss liked the picture of George Brett so much that they used it on two different cards in the 1981 set. Donruss used a cropped version of Reggie Jackson's prototype picture of one of his three cards in the 1981 set.
The most amazing aspect of the 1980 Donruss prototype is how similar it appears compared to the 1980 Topps set. Both feature flags wrapped around the top and bottom of the card and a large area for a picture.
Below is an uncut sheet of all three prototypes.