There's no clear favorite in this one, which could lead to an exciting race on Saturday. Olympian Courtney Frerichs, 2015 champ Laura Thweatt, Aliphine Tuliamuk, Sarah Pagano and Kellyn Taylor are the biggest names entered.

You'd better be tough (and talented) if you want to make the 2017 World XC team as the conditions are going to be difficult and the field is stacked with 8 of the top 9 from the Olympic 10,000 Trials. Derrick -- and almost everyone else -- missed out on last year's race, but he's back after three-peating from 2013 through 2015 but he'll have his hands full with the Kenyan-born talent in Scott Simmons group that is taking America by storm.

With Abbey D'Agostino out due to injury, the biggest name in the field is 2012 champ Sara Hall. Katie Mackey and Laura Thweatt, #3 and #4, respectively, on the U.S. list at 5,000 last year have good shots to make the team; U.S. Half Marathon Champs runner-up Brianne Nelson (70:16) will also run.

8 years ago, with World XC spots on the line, the action in Boulder was legendary as all of the Colorado greats - Culpepper, Goucher, Torres and Ritz - battled. What's in store in 2015? Chris Derrick goes for the three-peat but he'll have plenty of competition in the form of Ben True, Dathan Ritzenhein, Maksim Korolev, Ryan Vail and Garrett Heath.