Announcement of Introduction and Replacement
On June 14, 2012, it was announced that the character of Stephanie Brown would be introduced along with Batman in Smallville, taking the moniker not of Robin or Batgirl (in the comics both of these names have being used by Brown) but as Nightwing. The writer of Smallville: Season 11, Bryan Q. Miller, who also wrote the Batgirl series (2009-2011) starring Stephanie Brown, was quoted as saying “Bruce can be somewhat of an angry man. Stephanie’s personality is so can-do and unsinkable and bright, so it’s very much on purpose on Bruce’s part that he has a good cop going out on patrol with him every night.” In another interview Miller said about Stephanie “From a writer's standpoint, I felt I couldn't get any deeper into this without having Stephanie somewhere. This is the Stephanie that people who read "Batgirl" came to know and love. Not much of her has changed. She's just wearing a different costume.” On the choice of using the alias of Nightwing Miller said it will eventually be addressed as to why Stephanie is Nightwing and he commented “Choosing Nightwing as opposed to Robin just seemed like the nice kind of take we'd have done on the show so it's not exactly the same thing as the comics because there are a bunch of other comics where you can get that. We're doing our own take, which isn't too far from, in quotation marks, "how it's supposed to be," but it's our little corner of the world.” 
On July 12, 2012, it was reported that the character of Stephanie Brown wouldn't appear in the series due to last minute editorial changes, recoloring the art and changing dialog to boot. On July 14, 2012, it was confirmed by the Co-Publisher of DC Comics, Dan Didio, in DC Comics' The New Wave panel at San Diego Comic-Con that Stephanie Brown will be replaced by Barbara Gordon in Smallville. “That is true, and there’s a reason for it,” DiDio said in response to the fan’s question, noting that he supported the change from the original plan, as it falls in line with the Smallville practice of bringing the iconic versions of DC heroes into that television world. “If we’re going to introduce a character into the Smallville world, I want them to be the most iconic versions like Barbara Gordon or Dick Grayson, and maybe down the road we can do more.”  Despite several rumors indicating that DC Editorial asked Miller to replace Stephanie Brown with Barbara Gordon because the latter is more recognizable and thus likely to sell more comics, it was confirmed by writer Gail Simone that wasn't the case “Today, Bryan (Miller) told me it was his idea to use Babs, when asked to replace Steph.” the writer said on the matter, suggesting that it was Miller's choice to use Gordon rather than any other character and not because Gordon was more "iconic" as it was suggested by Didio.
Differences on the Nightwing costume
After Stephanie's replacement, the Nightwing costume was slightly changed to be more familiar with Barbara's usual style.
The colors in the costume and the mask were changed from black and purple (Brown's usual colors used in her Spoiler and Batgirl costumes) to dark blue and yellow (Gordon's characteristic colors in her Batgirl costume), but other than that the design of the costume remained the same. Moreover the hair color was also changed from purple to red. The fact that in her civilian persona Barbara has longer hair, as seen in her appearances in Smallville, suggests that the short hair she wears while on disguise as Nightwing is a wig. This also explains Stephanie's original Nightwing look, which had her with short purple hair, suggesting that was also a wig with her real hair being blonde, as she is usually depicted.