In Bejing he was second mzungo with a 9th place finish and London is his fourth turnout on the Marathon distance. The Bookies give him a interesting 125-1 for Sunday.
He competes professionally for Nike, and is coached by Brad Hudson.
Ritzenhein began his professional career on December 31, 2004 when he finished 3rd in a 10 km road race in Italy. In January 2005 he won the prestigious Belfast International cross country race, and seemed to be in great form. Ritzenhein won the U.S. Cross Country Championships in the 12 km for his first senior national title. Before the World Cross Country Championships expectations were high and some prognosticators even predicted a top 10 finish, but Ritzenhein faded after going out with the leaders and ended up placing 62nd. Ritzenhein's 2005 track season began with a 13:22.23 5000m personal record and a 7:43.95 3000m. In a much anticipated 2 mile race that included high school rival Alan Webb, Ritzenhein ran 8:23.45, which was a solid performance, but was overshadowed by Webb's 8:11.48 for the American record. A few days before the U.S. Outdoor Track Championships Ritzenhein injured a nerve on his foot while kicking around a soccer ball bare foot with his dog. This injury effectively ended his season.
On February 19, 2006, Ritzenhein faltered in the USATF national cross-country championships at Van Cortlandt Park. Leading with Hall and Jorge Torres for several circuits of the 12K course, he dropped off badly near the end as Ryan Hall ran away from the field. Ritzenhein finished nearly a minute behind Hall and finished fourth in the race. He qualified for the team but appeared to be hurting badly after the race, leading some to question his fitness heading into the IAAF World Cross-Country Championships April 1-2. Ritz was diagnosed with walking pneumonia after the USATF national cross-country championships and forfeited his spot on the US team.
He again competed against Alan Webb in a 10-km race at the Cardinal Invitational at Stanford University. Prior to the race Webb and Ritz agreed to alternate leading the race for the first 24 laps. The last lap would be "every man for himself." Webb's mid-distance background allowed him to outkick Ritz for the win. In the 5000 m at the U.S. Outdoor Track Championships Ritzenhein finished 3rd behind Bernard Lagat and Matt Tegenkamp. Ritzenhein's time of 13:16.61 was a personal record. He then went to Europe and ran two 5000 m races. He won his first race in Switzerland, and then ran respectably in an elite field in Rome.
Ritzenhein made his Marathon debut in the 2006 ING New York City Marathon, finishing in 11th place with a time of 2:14:01.Ritzenhein finished second (2:11:07) in the 2008 Olympic Marathon Trials which automatically placed Dathan on Team USA for the Beijing Olympics.
In the 2008 Olympic Marathon, Ritzenhein was the first American Runner to cross the finish line, finishing 9th with a time of 2:11:59. His teammate, Ryan Hall, finished just behind him in 10th place.
Ritzenhein is married to Rockford native and University of Colorado distance runner Kalin Toedebusch and the two have a baby girl. He currently lives and trains in Eugene, Oregon.
Mzungo.org says: "Will have trouble staying in a lead pack that is on World Record Pace. He gonna finish in a time of 2:09:02 on 8th place."