Philadelphia Eagles fans have a tough decision to make — dog mask or dog T-shirt? They both help a good cause, but the latter may be easier to find.

Offensive lineman Lane Johnson saw an opportunity in a viral trend that may leave the bleachers at Sunday's NFC championship game against the Minnesota Vikings littered with German Shepherd lookalikes. His plan, which benefits the School District of Philadelphia, has already raised more than $100,000.

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It started last Saturday, when the team's win against the Atlanta Falcons sparked Johnson and defensive lineman Chris Long to take the field in dog masks, paying homage to the Eagles' status as the first No. 1 seed to be an underdog in its first postseason game.

Thanks to the pair, the masks quickly sold out on Amazon, prompting Johnson to help out, a Philadelphia-based business, by stocking up on the hot item with 65 percent of proceeds going toward The Fund for the School District of Philadelphia, the not-for-profit arm of the schools, Johnson announced on Twitter Thursday.

But bad news fans — those masks too have sold out as of Friday morning. The website says it will "get more as soon as possible."

But still available are the limited edition T-shirts showing Johnson and Long in the masks with the phrase "HOME DOGS GONNA EAT" wrapped around the two players. More than 3,000 of the T-shirts sold in 24 hours, Johnson said on Twitter earlier this week. All proceeds from the shirts also go toward the fund.

Johnson said he's now raised more than $100,000 for the cause.

"I've been doing playground builds here every year," he said. "I see what these kids have and it's not a whole lot. You got teachers that are supposed to be leading the new generation of girls and guys. And they need all of the resources they can get. Where I came from and looking what these kids have, they need all the help they can get."

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The $18 T-shirts have "no guaranteed delivery date," but the website that shirts are "being shipped daily."

School District spokeswoman Megan Lello said that the schools are "grateful" for Johnson's partnership.

"The generous support of our schools provided by Mr. Johnson through his LJ65 line, in addition to his work ethic both on and off the field, goes a long way in helping our students across the city to succeed," she said in an email. "We look forward to continuing to root for the Eagles and working together to make sure our students have access to exciting educational opportunities."

The shirts aren't the first time an Eagle's philanthropic efforts have made news. This past season, Long donated his own salary and launched Pledge 10 for Tomorrow, a campaign to improve educational opportunities in Philadelphia, Boston and St. Louis — the three NFL cities he's played in. The effort was recently recognized by former President Barack Obama.

Staff writers Zach Berman and Paul Domowitch contributed to this story.