The phrase "leading contender" means someone or something that is viewed as having the highest chance of winning or being successful in a competition or situation. Full definition
In anticipation of the announcement, 21 vehicle models have been identified as leading contenders. (sema.org)
And yes, both are viable leading contenders this year. (variety.com)
De Blasio hastened to add that he'd also met with Police Chief Philip Banks III and First Deputy Commissioner Rafael Pineiro, both of whom have been mentioned as leading contenders for the job. (dnainfo.com)