The biggest names in beach volleyball are flocking to Rio de Janeiro this week. The FIVB Rio Four Star is the highest-level international event since the Fort Lauderdale Five Star in February, and the world's best athletes are chomping at the bit to compete again and kick off the 2017 season in earnest on Tuesday, May 16, to Sunday, May 21.

Three U.S. men's pairs and four women's pairs will play in Rio, but they are not the only teams you should be watching throughout the event. Here are four storylines we'll be following:

1. Gold medalist Laura Ludwig is back on the sand.

Only months after winning gold at the Rio Olympics with partner Kira Walkenhorst, Laura Ludwig had surgery on her right shoulder. Walkenhorst played with Julia Grossner at the Fort Lauderdale Five Star event in February, finishing 17th, while Ludwig continued to recovery. In Rio, however, Ludwig will be making her triumphant return to the FIVB tour. Already, the German pair has been back in action, competing on the German Smart Tour and winning the most recent event in Munster.

2. No more NCAA restrictions for Sara Hughes and Kelly Claes.

Everyone's favorite college beach volleyball pair is finally free of NCAA restrictions and able to compete full time on the professional tours. Hughes and Claes played their first senior FIVB event in 2015, the Long Beach Grand Slam, and played two events last summer, finishing 17th at the Klagenfurt Major and ninth at the Long Beach Grand Slam. At the Fort Lauderdale Five Star earlier this year, Claes played with Kelly Reeves, finishing 17th, and Hughes played with Lauren Fendrick, taking ninth.

Over their careers, Hughes and Claes have made a combined $66,575 on the AVP and FIVB tours but have not been able to accept the money due to NCAA restrictions. This week, however, they'll finally be competing as full-time pros. Watch out, world!

3. All three men's Rio Olympics medalists pairs will be competing.

Reigning Olympic gold medalists Bruno Oscar Schmidt and Alison Cerutti of Brazil, silver medalists Daniele Lupo and Paolo Nicolai of Italy, and bronze medalists Alexander Brouwer and Robert Meeuwsen of the Netherlands have all continued their partnerships into 2017 and will be fighting for a podium finish at the Rio Four Star.

Bruno and Alison took fifth at the Fort Lauderdale Five Star earlier this year after losing to Phil Dalhausser and Nick Lucena in the quarterfinals. Lupo and Nicolai also finished fifth in Fort Lauderdale, losing to John Hyden and Ryan Doherty in the quarters; however, the Italian duo won silver in the Xiamen Three Star event last month. Brouwer and Meeuwsen did not play in Fort Lauderdale, but they won the Xiamen event, defeating Lupo and Nicolai in the gold medal match.

4. Mr. Skyball returns to Rio.

Italy's Adrian Carambula is a fan favorite thanks to his incredible defense, crafty shots, and, of course, his skyball serve. The 2016 Olympian who finished ninth in Rio with Alex Ranghieri could not play at the Fort Lauderdale Five Star due to unresolved U.S. visa issues but will hit the sand in Rio, playing for the first time since the 2016 World Tour Finals in Toronto.