According to sources within WWE, they have heard nothing about this and it appears to be just another internet rumor that blows up and get people talking. There has been nothing released that would indicate this rumor having any real truth to it at this time.
Given that Borden is well into his 40’s and well off financially, many don’t ever see him signing a deal to appear for WWE. There was talk of wanting to bring him in for WrestleMania involving The Rock, but those plans never came about and since then there has been no approach by WWE ever again to bring him into the company. Sting made his last pro wrestling appearance in the United States for TNA back in March of 2004 and wrestled his last match against Billy Gunn in Korea for Mid-Atlantic Championship Wrestling in January of 2005.