Union’s Mark McKenzie, Brenden Aaronson and Matt Freese on USMNT Olympic qualifying roster

Union centerback Mark McKenzie, midfield playmaker Brenden Aaronson and goalkeeper Matt Freese are on the U.S. under-23 national team’s 20-player roster for Concacaf’s Olympic qualifying tournament, which will run March 20-April 1 in Guadalajara, Mexico.

The selections of McKenzie and Aaronson were no surprise, as both have been open about the subject for months. Freese’s selection was a surprise, and a real feather in the cap of a player who turned pro last year after leaving Harvard as a sophomore.

The U.S. men haven’t qualified for the Olympics since 2008. While the tournament isn’t as big a deal on the global soccer scene, as an under-23 age group event, it can still be a significant step for young players. The event also matters more here than in other countries, because the Olympics as a whole do.

If the Americans do make it to Tokyo, they’ll be allowed three overage players on their 18-player squad. The U.S. Soccer Federation also will try to get young Europe-based stars such as Hershey native Christian Pulisic on the roster. Expect U.S. Soccer to mount a strong lobbying effort this spring if they get the chance.

Clubs aren’t required to release players for the Olympics and qualifiers the way they must for major senior-level tournaments. So it’s quite a coup that U.S. Soccer got four Europe-based players onto the qualifying team, even if they don’t play much for their clubs: defenders Chris Gloster and Erik Palmer-Brown, midfielder Richard Ledezma and forward Ulysses Llanez. There’s also one Mexico-based player, forward Sebastian Saucedo.

The qualifying squad is mostly all domestic because MLS clubs work more with the national team — though less than they used to. Atlanta United barred its players, including promising centerback Miles Robinson, from taking part. Some teams also persuaded U.S. Soccer to let players come late to the pre-qualifying training camp, which starts Monday.

We won’t know how much of a fight the Union put up, but all sides get that McKenzie and Aaronson will be important players on the qualifying team, so they’ll arrive on time.

Goalkeepers (3): Matt Freese (Philadelphia Union), JT Marcinkowski (San Jose Earthquakes), David Ochoa (Real Salt Lake)

Defenders (6): Reggie Cannon (FC Dallas), Justen Glad (Real Salt Lake), Chris Gloster (PSV Eindhoven, Netherlands), Aaron Herrera (Real Salt Lake), Mark McKenzie (Philadelphia Union), Erik Palmer-Brown (Austria Wien, Austria)

Midfielders (6): Brenden Aaronson (Philadelphia Union), Hassani Dotson (Minnesota United), Richard Ledezma (PSV Eindhoven, Netherlands), Djordje Mihailovic (Chicago Fire), Paxton Pomykal (FC Dallas), Jackson Yueill (San Jose Earthquakes)

Forwards (5): Jeremy Ebobisse (Portland Timbers), Jesús Ferreira (FC Dallas), Jonathan Lewis (Colorado Rapids), Ulysses Llanez (VfL Wolfsburg, Germany), Sebastian Saucedo (Pumas UNAM, Mexico)

There are two groups of four teams each. Group A has the U.S., Mexico, Costa Rica and the Dominican Republic; Group B has Canada, El Salvador, Honduras and Haiti. The top two teams in each group will advance to the semifinals, and the winners of those games will book Olympic berths.

The Americans are likely to finish second in their group, behind Mexico.

All games will be in Guadalajara, Mexico. Fox Sports and Univision have U.S. broadcast rights to the tournament, in English and Spanish, respectively.

7 p.m.: United States vs. Costa Rica

9:30 p.m.: Mexico vs. Dominican Republic

3:30 p.m.: Canada vs. El Salvador

6 p.m.: Honduras vs. Haiti

7 p.m.: Dominican Republic vs. United States

9:30 p.m.: Costa Rica vs. Mexico

7 p.m.: Haiti vs. Canada

9:30 p.m.: El Salvador vs. Honduras

8:30 p.m.: Costa Rica vs. Dominican Republic

11 p.m.: Mexico vs. United States

7 p.m.: El Salvador vs. Haiti

9:30 p.m.: Honduras vs. Canada

7 p.m.: B1 vs. A2 semifinal

10 p.m.: A1 vs. B2 semifinal

10:30 p.m.: Tournament final