COMMERCE CITY, Colo. – The quest for playing time continues for Colorado Rapids Homegrown players Dillon Serna and Shane O'Neill.

Recently selected to the US Under-23 Men's National Team roster for the 2015 Toulon Tournament, the pair will likely see the pitch for Andi Herzog’s side at the prestigious competition in France. While they’ve both found solace on the international level, time has been hard to come by in Colorado, with the two combining for just 331 minutes played this season.

The fight for minutes has been a particularly trying experience for the 21-year-old Serna, who appeared in 27 games and made 18 starts in 2014.

“I have been a bit frustrated so far,” Serna told MLSsoccer.com when asked about his lack of playing time this season. “These are times where you have to use the frustration as motivation. That’s the only option that will make me better. I can’t feel sorry for myself. I can’t come into training and not work hard.”

Serna offers versatility as an option in midfield and at left back; a position where the Brighton, Colo. native appeared as a late-game substitute in the Rapids’ 3-1 loss to Seattle on April 18. But, with offseason additions and healthy veterans at Rapids head coach Pablo Mastroeni’s disposal, Serna has had to scratch and claw for his six appearances this season – all but one of which have been off the bench.

“I think the competition of the group is ten-fold of what it was last year,” said Mastroeni, who has looked to establish consistency this season following a disastrous 2014 campaign. “At this point I feel like we’ve been a really consistent team. Shakeups really occur when people need breaks, when there’s injuries and there really hasn’t been too many opportunities available.”

In midfield, Serna is competing in a crowded group of wingers that includes Designated Player Juan Ramirez, Vicente Sanchez and a rejuvenated Gabriel Torres. At left back, Colorado now features a healthy Marc Burch and Michael Harrington, who have both contributed to a defense which has allowed just nine goals in 11 games.

“It’s definitely a step up from last year,” Serna said. “There’s a lot of experienced guys in our locker room now so there is a lot more competition, but it’s a good situation. The competition will bring the best out of all the players, not just myself.”

A fight for playing time in the professional ranks isn’t unique to Serna and O’Neill. In fact, it’s been a common theme for the MLS players on the Toulon roster. Of the six MLS players selected to the roster for Toulon, only San Jose’s Fatai Alashe (758 minutes) and Orlando’s Tyler Turner (257) have logged more time than Serna (135) and O’Neill (198) this season.

Serna is the only other U-23 player besides Alashe to score a goal in MLS this season, but in Toulon, his focus will shift as one of the seven defenders selected.

“When I get those opportunities, I’ve got to take advantage there,” Serna said. “I can’t take any days off.”

After all, it’s hard work that will be the determining factor in not only success at the international level, but back at home with Colorado.

“It’s been frustrating for me not seeing the same kind of success I saw last year but these are the moments that are going to build my character and become the player I want to be,” he explained. “Every player goes through these times. I’ve just got to come in every day and keep working as hard as I can.”