Daunting challenges await Maria Sharapova when she returns

— -- Russian tennis star  Maria Sharapova scored a significant victory in court Tuesday when the Court of Arbitration for Sport upheld her appeal and reduced her two-year suspension for doping to 15 months. Equally daunting challenges await Sharapova on a very different court when she's eligible to play on the WTA Tour again in April.

The landscape in women's tennis has changed dramatically since Sharapova was suspended shortly after the Australian Open. In one way, this is good news for the 29-year-old. Serena Williams is 35, injury-plagued and increasingly prone to playing poorly -- or in the grip of anxiety. Sharapova is a five-time Grand Slam champ who owns a career Grand Slam. But that 2-19 record against Williams is a glaring stain on her resume. A few wins over Williams in the near future would make the mark less noticeable.

The general feeling is the WTA is in transition to a post-Williams era. It's a great opportunity for Sharapova to insert herself back into the conversation -- and perhaps find a way to get back to a top ranking she most recently held for four weeks in 2012. But new voices want to make themselves heard -- and time is on their side.

Few would have predicted Angelique Kerber, 2015's No. 10-ranked player, would appear in three Grand Slam finals this year, winning two. Garbine Muguruza, 22, was a Grand Slam finalist at Wimbledon in 2015; this year, she won the French Open, beating Williams in the final.

When Sharapova played her last WTA match (Williams crushed her 6-4, 6-1 in the Australian Open quarterfinals), neither Karolina Pliskova nor Madison Keys were anywhere near the top 10. Johanna Konta was not yet emergent. Now they all are significant forces, and they can match Sharapova in an enterprise that was once practically her private domain: power tennis.

The one player who can't meet the standard, Kerber, is now No. 1 largely because she has mastered the art of neutralizing the kind of heavy serving and baseline blasting that the power players represent. Even before Kerber's transformation into a more aggressive, confident player, Sharapova was just 4-3 against her.

Pliskova, a player who has much in common with Sharapova style-wise, was beaten by Kerber in the US Open final.

"I don't know any other player, Simona [Halep] or those girls, which are running [as much as Kerber]," Pliskova said after the match. "I cannot play really 30 times across the net. It's gonna just kill me, and I will not in the end even win it."

Pliskova rushed the net 38 times in the final, when she realized it was the only way for her to escape those unwinnable baseline duels. Sharapova might find herself in a similar boat when she plays Kerber. And Kerber is just one player. The problem for Sharapova is that the threat is general and has multiple layers.

She will need to beat opponents whose success comes from being able to fend off and frustrate hard hitters, players who will make Sharapova hit one more ball. And she will have to master the cohort who can beat Sharapova at her own game.

Kerber leads that former group because of the quality of her return game, as well as her baseline proficiency. As service bombardier Pliskova observed: "The other girls, they are missing so much the returns. [Kerber] is not."

No. 4-ranked Muguruza is in that category as well. She's a strong 6-footer who plays a punishing, powerful baseline game. Former No. 1 Victoria Azarenka, who is inactive and due to give birth at the end of the year, might be back at about the same time as Sharapova, who just leads their rivalry 8-7.

Add the jackrabbit-quick Halep, who's overdue for a breakout, along with familiar faces such as Svetlana Kuznetsova and Dominika Cibulkova to the pool.

The other problematic group for Sharapova is the ever-expanding lot of players who can match the Russian serve for big serve or beat her at first-strike tennis. Pliskova and steadily maturing 21-year-old Madison Keys are the leading young members of that group.

Williams always enjoyed a power and mobility advantage. Petra Kvitova can overwhelm Sharapova as well. Kvitova is just 26 and a two-time champ at the tournament where Sharapova ought to be most effective but has won just once, Wimbledon.

The power group also includes 36-year-old Venus Williams and Konta, 25.

The one component that can't be factored in this comeback is Sharapova's legendary competitiveness. Her toughness is unparalleled. She's been a master intimidator.

However, command is earned and confidence is cumulative. When Sharapova returns, she will enter tournaments as a wild card with no ranking, her tank empty of W's -- that once steady flow of assurance cut off and dried up. It takes a lot of match play to get back your confidence, as Rafael Nadal can attest.

Sharapova has always kept her distance from her peers and rivals, which won't make her return any easier. Nobody will be decorating the locker room with "Welcome Back!" banners. That might not matter to her, but it will to her rivals. Nobody will want to be to one Sharapova walks over to get back to the top.