ARLINGTON -- Many Mariners were sporting a new look as they lounged in the visiting clubhouse at Globe Life Park in the hours leading up to batting practice and first pitch of their four-game series opener on Thursday.

They're wearing Seattle-themed "Unity" T-shirts, courtesy of reliever Sam Tuivailala, who is supporting sales of the T-shirts to raise funds for impoverished citizens of the Dominican Republic. Through Big League Impact, sales of the Athletes Brand-designed T-shirts go toward helping those in need to obtain sustainable food and clean water, with funding also going toward the construction of baseball fields.

The "Unity" insignia includes designs unique to Seattle. The "I" is a shaped like the city's famous Space Needle, and parts of the "I","T" and "Y" show a depiction of the roof of T-Mobile Park. Fans can order the shirts here.

"I thought it would be pretty cool to involve Seattle, get the guys involved with it," Tuivailala said.

There are five styles of the Seattle-themed Unity shirts -- four for adults, one for youth -- according to the Athletes Brand collections section of its web site.

Tuivailala became involved with Big League Impact through his former Cardinals teammate, Adam Wainwright, who founded the organization. During one offseason, Tuivailala saw photos of Wainwright and a few other Major Leaguers doing work for the organization in the Dominican Republic and asked how he could become involved.

"When Spring Training came along, I asked him if there was a way to join the team and help out," Tuivailala said. "[Wainwright] introduced me to all the guys at the Big League Impact team and we just kind of went from there."

Big League Impact raises money by inviting fans to participate in various activities that athletes enjoy, such as fantasy football, March Madness, karaoke and e-sports.

For example, on Saturday, Wainwright will host the seventh annual "Waino's World Fantasy Football Draft" at Busch Stadium.

Money raised from all activities goes toward "impact causes" -- water, sustainable farming, health and medicine, infrastructure, schools and education and humanitarian aid. Funding is distributed worldwide.

Wainwright founded Big League Impact in 2013, and, according to its web site, more than 30 Major Leaguers are currently involved in some capacity. The organization has raised more than $3.1 million.

"He's one of those guys you look up to," Tuivailala said of Wainwright, his teammate from '14 until last season, when the reliever was traded to the Mariners. "He's a great role model on and off the field. When we see him helping out others in his free time, you just want to follow in the footsteps. I think he laid down a really good path for us, and we're trying to do as much as we can off the field."