Aliya Mustafina might need to bring her “A-game” to Jacksonville after all.

The newly crowned world champion was absolutely invincible less than five months ago at her first worlds outing in Rotterdam, and was expected to dominate this weekend’s American Cup, particularly after fellow world medalists Jiang Yuyuan and Rebecca Bross declined invitations to compete.

Great Britain’s Nicole Hibbert, a solid all-arounder who placed 22nd overall at the 2010 world championships, was recently injured at the British nationals and forced to withdraw from this weekend’s competition.  She’ll be replaced by a gymnast whom many consider to be one of only three women in the world capable of challenging the reigning queen from Russia – American sensation Jordyn Wieber.

The fifteen-year-old Jordyn Wieber won the 2009 American Cup at just thirteen years old and has been unstoppable in the junior ranks ever since, frequently outscoring the world’s top senior gymnasts and serving notice that she may be the next world star as soon as she became age eligible.  Well that opportunity has finally arrived, perhaps a bit sooner than she or her coach had anticipated.

Defeating the world champion in her first major international meet as a senior would certainly be a lofty goal, but Wieber may very well be up for the task.  Event for event, Wieber stacks up quite nicely against the world champion in both difficulty and execution.  The two phenoms each compete the same gutsy vault – a Yurchenko with a 2 ½ twist – and have similar difficulty scores on beam and floor.   The spectacular double-double that Wieber unveiled at last summer’s Covergirl Classic placed her already strong floor routine on a par with any gymnast in the world.  Bars is the one event where the American lags behind the Russian in difficulty, but her solid handstands and clean work always allow her to still score well.  The biggest question mark for Wieber will be how she handles the pressure of going head to head with the best gymnast on the planet – in the biggest meet of her life and on live television.

Other potential challengers to the two headliners include American Aly Raisman, China’s Huang Quishuang, and Australia’s Lauren Mitchell.  Raisman exploded onto the senior scene last year with a 2nd place finish at the American Cup, a 3rd place finish at the U.S. Championships, and an incredibly solid performance at her first world championships.  The cool and collected Raisman placed a stunning third all-around in preliminaries in Rotterdam, and then unfortunately missed her weakest event, uneven bars, in the all-around finals and finished 13th.  She’s planning to compete the same risky vault we’ll see from Wieber and Mustafina this weekend, an upgrade that could potentially catapult her much closer to the two favorites…if she hits it.

The occasionally unpredictable Huang Quishuang finished 4th in Rotterdam, even with less-than-stellar performances on beam and floor.  A consistent four-for-four effort will certainly keep this exquisite gymnast in contention for at least a medal in Jacksonville.  And Lauren Mitchell is most known for her work on beam, where she was a 2009 world silver medalist, and floor, where she is the current world champion, but her all-around potential has skyrocketed in the past two years, as has her confidence.  If the favorites make major mistakes this weekend, the popular Mitchell could easily step in for the win.

Finally, Switzerland’s Ariella Kaeslin, Venezuela’s Jessica Lopez, and Great Britain’s Hannah Whelan won’t be expected to challenge for the title, but all three will provide delightful variety to the competition.  Both Lopez and Kaeslin were extremely solid at last year’s American Cup, where they placed 3rd and 4th, respectively, as well as at the world championships, where they each finished in the top ten.  And Hannah Whelan, 16th in Rotterdam, just won the British National Championships and should be in excellent shape to showcase her clean gymnastics in front of an energetic American crowd.