By Darci Miller | July 19, 2017, 11:58 a.m. (ET)

Forty-five athletes are in Budapest, Hungary, to represent USA Swimming in the pool at the 2017 FINA World Championships. Ten of those athletes -- many of whom are 2016 Olympic medalists -- are 2015 world medalists looking to defend their hardware.

Here's a look at the defending medalists and a primer on their outlook for 2017.

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Nathan Adrian

Medals in 2015: 50-meter freestyle silver, 4x100-meter medley gold, 4x100-meter mixed freestyle gold

Events in 2017: 50-meter freestyle, 100-meter freestyle

Outlook: Adrian is a two-time Olympic medalist in the 100 free, but he also has a strong chance to medal in the 50 free and any relays he’s added to.

What’s happened since 2015: Adrian has been at the top of USA Swimming since 2008, and that didn’t change in 2016. Competing at his third Olympic Games in Rio, he won golds in the 4x100 medley and the 4x100 free, and individual bronzes in the 100 free and 50 free.

 

Kevin Cordes

Medals in 2015: 50-meter breaststroke bronze, 200-meter breaststroke silver, 4x100-meter medley gold, 4x100-meter mixed medley silver

Events in 2017: 50-meter breaststroke, 100-meter breaststroke, 200-meter breaststroke

Outlook: Cordes excels in the 100 breast, finishing just off the podium in fourth in Rio. He could pull in a medal here as well as in the relays.

What’s happened since 2015: Cordes made his Olympic debut in 2016 and, while he finished off the podium in his individual events, won gold in the 4x100 medley. He returned to top form in 2017, winning three events at nationals.

 

Conor Dwyer

Medals in 2015: 4x200-meter freestyle silver

Events in 2017: 4x200-meter freestyle

Outlook: Dwyer is an eight-time world championships medalist, so the odds are on his side. With a team of newcomers Zane Grothe, Jay Litherland and Clark Smith, he should be in the podium hunt.

What’s happened since 2015: Dwyer competed on his second Olympic team in Rio, where he won 4x200 free gold and 200 free bronze. He took some time off following the Games but got back into the swing of competition in June at the Arena Pro Swim Series stop in Santa Clara, California. He finished fourth in the 200 free at nationals to earn his worlds relay spot.

 

Matt Grevers

Medals in 2015: 50-meter backstroke silver, 100-meter backstroke bronze

Events in 2017: 50-meter backstroke, 100-meter backstroke

Outlook: As the 2012 Olympic champion in the 100 backstroke, Grevers is the longtime king of backstroke in the U.S., and he is hoping to reign supreme again in his signature event… if he can hold off compatriot Ryan Murphy.

What’s happened since 2015: Murphy dethroned Grevers at the 2016 U.S. Olympic Team Trials, causing Grevers to miss out on his third Olympic team and the opportunity to defend his 100 back Olympic title. Rather than retiring, he kept training and once again beat Murphy at the 2017 national championships, earning his spot in Budapest.

 

Chase Kalisz

Medals in 2015: 400-meter IM bronze

Events in 2017: 200-meter IM, 400-meter IM

Outlook: With the fastest time in the world in the 400 IM, Kalisz looks primed to podium in the event again.

What’s happened since 2015: Kalisz made his first Olympic team in 2016. In Rio he competed in the 400 IM, winning silver. He blitzed the field in the event at the Phillips 66 National Championships, winning in a world’s-fastest time for his fourth title.

 

Katie Ledecky

Medals in 2015: 200, 400, 800, 1,500-meter freestyle golds, 4x200-meter freestyle gold

Events in 2017: 200, 400, 800, 1,500-meter freestyles, 4x100-meter freestyle

Outlook: Ledecky is the current world-record holder in the 400, 800 and 1,500 free and is expected to clean up yet again in Budapest.

What’s happened since 2015: What hasn’t happened since 2015? Ledecky’s potential appears to be boundless as she has earned herself the reputation as easily the best swimmer in the world. Ledecky competed at her second Olympic Games in 2016 and won four gold medals – in the 200, 400 and 800 free, as well as the 4x200 free – and a silver in the 4x100 free. Her world record in the 1,500 free was set at the 2015 world championships, while her latest 400 and 800 free records were set in Rio, where she routinely beat her opponents by multiple full seconds.

 

Simone Manuel

Medals in 2015: 4x100-meter freestyle bronze, 4x100-meter mixed freestyle gold

Events in 2017: 50-meter freestyle, 100-meter freestyle, 4x200-meter freestyle

Outlook: Manuel owns Olympic medals in both of her individual world championships events and has emerged as one of the best sprint freestylers in the world. She could find herself on the podium in each of her events.

What’s happened since 2015: Manuel had slowly been making a name for herself in the pool prior to 2016, but Rio was something of a coming out party. She won gold in the 100 free, becoming the first African-American female swimmer to win an individual Olympic medal, and silver in the 50 free, becoming the first U.S. woman to place in the top two in the 50 and 100. She also won gold in the 4x100 medley and silver in the 4x100 free. After Rio, she returned to Stanford, putting together a dominant collegiate season.

 

Ryan Murphy

Medals in 2015: 4x100-meter medley gold, 4x100-meter mixed medley silver

Events in 2017: 100-meter backstroke, 200-meter backstroke

Outlook: Murphy is the reigning Olympic champion in both of his individual events at worlds and should find himself on the podium in each of them.

What’s happened since 2015: Murphy ended Matt Grevers’ run as the undisputed king of U.S. backstroke at the 2016 U.S. Olympic Team Trials and went on to win three gold medals in his Olympic debut (100 back, 200 back and the 4x100 medley), which included breaking the 100 back world record.

 

Lia Neal

Medals in 2015: 4x100-meter freestyle bronze

Events in 2017: 4x100-meter freestyle

Outlook: U.S. relay teams are some of the strongest in the world, and Neal looks primed to reach the podium again with another fast squad.

What’s happened since 2015: The Olympic Games Rio 2016 were Neal’s second, and she won silver in the 4x100 free. After Rio, she returned to Stanford University, helping the Cardinal to the Pac-12 championship and the NCAA title.

 

Leah Smith

Medals in 2015: 4x200-meter freestyle gold

Events in 2017: 200, 400, 800, 1,500-meter freestyle, 400-meter individual medley

Outlook: Swimming in events dominated by Ledecky, Smith is no slouch herself and could find herself on the podium, particularly in the 400 free.

What’s happened since 2015: Smith made her Olympic debut in Rio and medaled in two of her three events: gold in the 4x200 free and bronze in the 400 free. Normally a freestyler, her coaches had her training the individual medley and had her enter the 400 at nationals. Surprising everyone, including herself, she won the national title in the event – her first career national championship.