FRISCO, Texas – They’ve both been donned the Red, White and Blue in some capacity in their careers, and they both also anchor a top-five MLS defense that ranks second in the league in clean sheets.

Yet neither of FC Dallas' center backs Matt Hedges and Walker Zimmerman received the call from Jurgen Klinsmann for the US national team's recent friendlies ahead of World Cup qualifying Hexagonal play next month.

“It’s disappointing for me and Walker,” Hedges told MLSsoccer.com. “We played well and thought maybe we’d get a chance in these. But maybe next one, who knows? We’ll keep doing what we’re doing – it doesn’t change anything.”

Hedges is coming off a career year in 2015, where he cracked the MLS Best XI for the first time in his career. This season, he’s already added another 2,000 minutes – the fifth straight time he’s reached that mark – and scored a crucial game-winning goal in the team’s US Open Cup win over New England.

With Zimmerman enjoying the healthiest stretch of his four-year career, the duo is helping make goalkeeper Chris Seitz look terrific, helping notch nine clean sheets, good for second in the league, while ranking 16th in MLS in saves.

Both Hedges and Zimmerman have started in 10 shutouts each for FC Dallas.

“They’ve proved this year they deserve to at least be in the thoughts of being called up for the national team,” said Ryan Hollingshead, who has played next to the two of them much of the season.

Added head coach Oscar Pareja: “I do think they have a chance [to be called up]. They should have a chance in the future. What we can control and what we can do is what they need to do here.”

Not receiving Jurgen Klinsmann's call may be disappointing to Hedges, but he, Zimmerman and Pareja all agree it’s nothing to hang their heads about. Instead, the message is simply continuing to do what they’ve been doing, and help FCD on their quest for the treble.

“If we work hard to finish out the season and have strong performances, that’s kind of doing everything we can do to try and earn that call,” Zimmerman told MLSsoccer.com, adding that he did not feel snubbed. “Coaches try to build their teams around what they want and what they’re looking for. At the end of the day, it’s about performing well and hopefully catching his eye.

“Whether that comes in January or years down the road, it’s something we’re always aspiring for and working for.”

Health has been a big factor in Zimmerman’s rise in stature. Starting in 28 MLS matches so far this season, he’s been able to gain comfort in all aspects of his game. Offensively, he has doubled his career best in goals with four, good for sixth best on the team and only one behind recently-departed star Fabian Castillo.

Defensively, the shutout numbers speak for themselves.

“They’ve gotten a lot of time together,” Hollingshead said of the duo. “The last couple of years, it’s been a lot of switching in and out and guys rotating through that center back spot. It just kind of makes it hard to get into a rhythm and get a relationship with the guy you’re playing next to, and I think because they’ve had such a long stretch together in there, they’ve really come into their own both on their own and together as a duo.”

A chance of getting that call-up in 2016 dwindles as the calendar pages continue to turn. But FCD’s defensive stalwarts remain undaunted.

“Hopefully that day comes sooner rather than later,” Zimmerman said. “And you’d better believe I’ll be ready whenever it does come.”