Photographs of Sterling training with England this week showed an M16 assault rifle depicted in a tattoo on his lower right leg, leading to a tabloid controversy.
Sterling explained his body art on social media, noting it is unfinished and intended as a tribute to his father, who was shot dead when the winger was two years old.
And as the debate continued to rumble on over Sterling's tattoo, Brazil international Fernandinho offered support to his City team-mate at a news conference on Thursday.
"He's one of our top players, he decided so many games for us this season, he was so important," Fernandinho said. "So we could mention so many things about him.
"The English press, the British press, they write about him and you can see some pursuit against him. He's a lovely guy, a nice guy and every day he is up and happy.
"I am so glad to share the dressing room with him and I don't know why people treat him like that. I am glad we have him. He's a lovely guy and never gives up even when he is criticised a lot."
Smile for the camera...but make sure you cover up your tattoos lads pic.twitter.com/UkrESNZgU3— Kyle Walker (@kylewalker2) May 31, 2018
City right-back Kyle Walker also backed Sterling with a pointed joke in a Twitter post.
"Smile for the camera..." Walker wrote alongside pictures he captured of John Stones and Danny Welbeck.
"But make sure you cover up your tattoos lads."
The Football Association has expressed its support for Sterling, describing the forward's explanation of the tattoo as an "honest and heartfelt account".