It won't be long before current Nike CEO Mark Parker replaces chairman Phil Knight, and as the changing of the guard nears, the race for the CEO position is heating up.

Nike Brand President Trevor Edwards has long been viewed as the favorite to succeed Parker, but Bloomberg reports that there's speculation that Edwards isn't a shoo-in just yet.

Not only is Nike's president of product and merchandising Michael Spillane winning over execs quickly, but Chief Operating Officer Eric Sprunk's name has also been discussed as a potential replacement. Meanwhile, it is considered possible, but unlikely, that Nike will find someone outside of the company to fill the role. 

According to Bloomberg, Spillane's rise has been especially impressive, with a total of five major promotions within the company over the last nine years. He's credited with much of Nike's recent success in China, an area which has been huge for the brand's growth. 

Analyst ​Brian Yarbrough praised Spillane's efforts, but ultimiately said that, "I think it's Trevor unless he does something that is detrimental to that path."