Upon the creation of the logos and jerseys, a special patch was created to mark the inaugural season. This patch was used in many promotional items and was sold in retail stores with all the original jerseys. It was also used in many studio shots of players, even as late as Spring Training 1998. However, before a game was ever played, the patch was changed to a different version, featuring a snake with a baseball in its mouth.
Despite the new patch, both were still used before the games began, and there seems to be no pattern as to which player wore which patch for their photos. Some even wore jerseys with no patch at all.
However, once the games actually started, every jersey worn during the season had the newer snake inaugural patch, including batting practice jerseys.
For the second season, the patch was altered slightly, as the inaugural wording was replaced with "Arizona." This is how the patch would stay until the uniforms were completely overhauled in 2007.
When looking at a photo, even one from a distance and with no other indicators of the year, you can often tell whether it has the inaugural patch or later version, simply by its shape. Because of the "1998" on the top of the inaugural patch, the two patches differ slightly.
Although the patch itself did not change before 2007, the use of it did. Starting in 2003, the undershirts of sleeveless vests no longer had the patch affixed.
Following the September 11th terrorist attacks in 2001, all MLB teams added American flag patches to the backs of the collars and sides of the caps. They were worn for the remainder of the season and playoffs, although the cap patch would be replaced in the World Series. The flag returned to the caps for special occasions in following years, such as Memorial Day and the Fourth of July, but special caps with the flag superimposed over the logo were used instead starting in 2008. The patches on the backs of the jerseys were only used in 2001. On the tenth anniversary in 2011, both the flag and jersey patches returned for one day.
During the 2001 World Series, both the Diamondbacks and Yankees wore special patches on the left side of their caps and right sleeves.
With the new uniforms of 2007 came a new patch, as the letters "D" and "B" formed the shape of a snake's head with its tongue sticking out.
This was used on all of the new jerseys, though there were some slight variations. As seen in the photo above, there was a white background, used for stitching the patch onto the jersey. This background color changed, depending on the color of the jersey. Different from previous jersey sets, the new patch was not used on the batting practice jersey.
Another slight modification was that the tongue was changed from black to red for the black jerseys.
It was not long before the patch was altered, as 2008 saw a few changes. Magician David Blaine had been using a similar logo, and he felt the Diamondbacks' logo was a little too close to be coincidental. To rectify the issue, the Diamondbacks added eyes to the snake and moved the tongue closer to the head. The tongue color also changed to red for most jerseys, with a black tongue for the red jerseys.
David Blaine's logo
Sleeve patch used in 2007
New logo for 2008
Another change for 2008 was the addition of a 10th anniversary patch to the right sleeve worn on all jerseys.
To mark the occasion of hosting the 2011 All Star Game, the Diamondbacks wore a right-sleeve patch all season.
2011 also saw a new innovation with patches, as players and coaches named to the All Star teams wore a special designation during the week leading up to the game. Game patches had regularly been worn during the game itself, but this was the first time there was any such use during a regular season game. Both the jerseys and caps had two gold stars added to the back, and the caps also had the game's patch added to the side.