Dathan Ritzenhein pulled out of the Denver Rock 'n' Roll Half Marathon on Wednesday, saying that race organizers were unable to assemble a deep enough field on short notice with the funding they had available.

"We wanted to get into an actual race where we'd have other people to run against," Ritzenhein said by phone from Albuquerque, where he's training. "It turned out that with the lack of time — and funding, really — we couldn't turn it into much more than a glorified training run."

Ritzenhein, the top American finisher at the 2008 Olympic men's marathon and a former distance runner at the University of Colorado, had intended to race hard in Denver on Sunday, he said, using it as a tune-up before the Nov. 7 New York City Marathon, his primary racing focus for this year. He acknowledged that culling a competitive field quickly in Denver — about three weeks — was "a big demand."