Phelps is the two-time defending gold medalist in the event, claiming the crown in Athens and refusing to relinquish it in Beijing. Now he'll be looking for the three-peat in London, racing in what is likely his final 200 IM on the world's biggest stage.
As the greatest swimmer of all-time, Phelps is certainly a threat to take home the gold on Thursday. It won't be easy though, as the field is packed with talented swimmers, many of whom know that they are capable of taking down the champ.
The following men are the top contenders to snatch the 200 IM gold away from Phelps.
Ryan Lochte, USA
Although the Olympics are a different stage, Lochte has already dethroned Phelps as the best 200 IM swimmer on the planet. He is the current world-record holder in the event, which he set by swimming the race in one minute, 54 seconds on his way to the gold medal at the 2011 World Championships.
He has also proved that he can beat Phelps in London, destroying him in the 400-meter IM on Saturday. Lochte crushed the rest of the field and beat Phelps—who finished fourth—by more than four seconds.
Phelps is still capable of beating his compatriot and rival, but I'm expecting Lochte to walk away with the gold on Thursday.
Thiago Pereira, Brazil
Like Lochte, Pereira has already beaten Phelps in London. The Brazilian took silver in the 400 IM, beating out Phelps by 0.42 seconds.
He was also excellent in the 200 IM semifinals, finishing second in his heat and fourth overall with a time of 1:57.45. Only Lochte, Phelps and the final man on our list finished ahead of him.
I doubt Pereira will win gold on Thursday, but he can definitely beat Phelps and earn his second medal of the Games.
Laszlo Cseh, Hungary
Cseh has been a force on the international swimming scene for nearly a decade now. He won bronze in the 400 IM in Athens, then took home three silvers from Beijing, including the 200 IM.
He has also excelled in the event in recent years, including his bronze in the 2011 World Championships. Only Lochte and Phelps beat him in that race.
In London, Cseh looks primed to medal once again in the event. He won his heats in both the qualification and semifinal rounds, and only Lochte posted a better time in the semis than Cseh's 1:56.74.
If he can slightly improve on that time in the finals, Cseh will have a good chance of ending Phelps' 200 IM dominance at the Olympics.
Others to Watch: Kosuke Hagino, Japan; Chad le Clos, South Africa