The ATP and WTA's big name stars are bound to make headlines this season, but what about the next tier of players who are looking to shake things up and compete with the top contenders. Here's a look at ten players to keep an eye on as the 2015 season begins.
Juan Martin del Potro
Can a Slam winner who stands 6-foot-6 really be under any radar? Probably not. But Del Potro's return is one of the most highly-anticipated stories of 2015 after a left wrist injury ended his season (and any momentum he gained from 2013) in February of last year. The Argentine underwent surgery in March and has undergone rehabilitation. He was scheduled to play in Brisbane International next week but withdrew from the tournament on Wednesday, citing a left wrist injury.
In a just world where everyone is born with bionic wrists, the 26-year-old would have been a Top 5 stalwart for the last five years. Now he's down to No. 137 in the rankings and will need to use his protected ranking wisely -- and get some help with wildcards -- to earn some wins and get his ranking back up.
A threat at any tournament he enters, Del Potro needs to focus on being (and staying) healthy once again. He'll be unseeded at nearly every tournament he enters for the first few months of the year, which means his name is the one to highlight when the draws come out.
In the same vein as Del Potro, no one will be ignoring Azarenka. The two-time Australian Open champion is coming off an injury-plagued season that included a respectable summer comeback -- consisting of a run to the quarterfinals of the U.S. Open -- before she shut down her season just a few weeks later. Now ranked No. 31, Azarenka is slated to play in next week's Brisbane International, where she made the final last year. A poor showing could mean she will go into the Australian Open unseeded, and a substandard performance there could plummet her ranking even further.
As a pure competitor she is second to no one. But the biggest question is whether Azarenka has put her injury woes behind her and worked her body back to full fitness. She didn't look like the same player during her three-month comeback last year. The physical and technical rust was evident. But at her best she's the only player on the tour who can regularly challenge Serena Williams. Her return to form would be big for the WTA.
We've said it before when discussing Monfils, but his transformation into a consistent winner and Top 10 player could change the game. His athleticism and charisma electrifies crowds and inspires kids to pick up a racket. He makes tennis cool.
2014 was a big step forward for Monfils. Playing without a coach throughout the year, Monfils still had his space cadet moments, but the highs were far more frequent and consistent. He came within shouting distance of potential season-changing wins over Novak Djokovic (Toronto), Roger Federer (U.S. Open) and Andy Murray (French Open). He got himself back into the Top 20 to finish the season at No. 18. And he did it all in style.
Monfils finished the season with a demonstrative win over Federer, handing the No. 2 the worst Davis Cup loss in his career. He then played the off-season IPTL and showed off his exhibitionist tennis and had a blast. All in all, Monfils is in a good place mentally these days. Look for that to bleed into his tennis.
When it comes to the WTA's youth, the spotlight over the last few years has been squarely focused on the likes of Laura Robson, Sloane Stephens and Eugenie Bouchard. Could Muguruza be next in line? The Venezuelan-born Spaniard had a breakout 2014 season, with her first WTA title at the Hobart International and first Slam quarterfinal at the French Open, where she beat Serena. Her inconsistency throughout the year was expected given her experience level, but talk to her for five minutes and it's clear she's not short on ambition. She is currently ranked at No. 20 but a Top 10 finish in 2015 would not surprise me.
Will 2015 be the year Keys steps out of the shadows, sheds her unassuming and humble nature and puts her stamp on the WTA? She leaves leaves the safe confines of the teenage ranks in February and is already No. 3 on the American depth chart behind Serena and Venus. Lindsay Davenport signed on as a coach should be a huge boost of confidence and if Davenport can help her become a better competitor while reigning in her often times overly-ambitious hitting, there's no reason Keys shouldn't be Top 20 by the end of the year.
For as much hype as Kyrgios is afforded -- and I'll say that I'm one who believes the hype is deserved -- let's not forget that he didn't play a ton after his breakthrough win over Rafael Nadal at Wimbledon.
He played just three tournaments (and went 3-3) the rest of the year due to a combination of injuries and fatigue. The 19-year-old is still unproven and there are questions percolating in Australia about his work ethic and physical fragility.
Kyrgios' 2015 already has an ominous start. After an off-season that saw him light it up on the IPTL, he's pulled out of next week's Hopman Cup citing a back injury. Can the youngster withstand the rigors of a full season?
Is Goffin for real? We spent the second half of the season celebrating his incredible run through the ATP's lower levels -- he went 44-4 after Wimbledon -- going from No. 106 to No. 22 in the span of five months. It was a heck of run that had everyone wondering whether the diminutive Belgian could do it against the ATP's best. Now we'll find out.
The good news for Goffin is all signs seem to indicate he can do it. In his last two tournaments of the year -- the Paris Indoors and Swiss Indoors -- he beat Milos Raonic en route to the Basel final where he lost to his idol Roger Federer. The following week he took David Ferrer the distance in Bercy.
The bar is set low for Stephens as she goes into 2015. Some of that is her own doing -- she went from No. 11 to No. 36 last year -- and some of it is just the cruel "what have you done for me lately" nature of the sport, which has moved on to anointing Bouchard as the current "It Girl." None of this is necessarily a bad thing for Stephens, who seemed unprepared for the searing heat of the spotlight after beating Serena at the Australian Open to make the semifinals in 2013. As the expectations soared she went from amused, to resentful, to withdrawn and ended her season abruptly in September due to a wrist injury. On Thursday she hired coach Nick Saviano to join her team beginning in Hobart this month, and as 2015 begins, she has no streaks to protect or results to defend and can just get back to building her career.
Is Sock the future of American men's tennis? The 22-year-old has emerged as the lone bright spot in the American youth corp. and is now being mentored by James Blake, a man who knows a thing or two about how to play that grip-and-rip style.
The kid has a world-class forehand and big serve that will help him stay in it with the best of the best, but he still lacks discipline in his decision-making. Can Blake help him reign it all in?
Up to No. 42 after a workmanlike 2014 season, Sock will have a delayed start to the season after undergoing hip surgery in the off-season. We won't see him until February at the earliest.
The 17-year-old is poised for a very big year. Up to No. 32, the Swiss teen will no longer have to waste her time in qualifying matches and will have more opportunities to go deep in tournaments and test herself against the game's best. After her run to the U.S. Open quarterfinals (where she was racked by nerves and easily beaten by Peng Shuai) she showed that she is able to make an impact at the Slams and her game translates to all surfaces (she won junior titles at the French Open and Wimbledon). Look for her to set a bevy of teenage milestones this season.