John Isner, naked, on a shirt

They say that grandparents will do anything to show how proud

they are of their grandchildren. This would be Exhibit A.

Tennis player John Isner posed for ESPN’s The

Magazine’s Body Issue without much fanfare (unlike a certain

href="http://msn.foxsports.com/tennis/story/agnieszka-radwanska-photos-facebook-response-ESPN-body-issue-071913">other

person we know) until his grandfather decided to rock this

shirt:

Now that’s taking pride in your grandkids. Funny thing,

Isner’s

href="http://legacy.tennis.com/players/player_bio.aspx?player_name=John+Isner"

target="_blank">tennis.com bio lists his nickname as

“Grandpa.” We may now know why.