The gesture started with a couple of players over the weekend but has grown to include most members of the team, including coaches, with each sporting a shaved head or a buzz cut.
Second baseman Jason Kipnis called it a "team thing."
"It started kind of with Mike Aviles' daughter, for her, what she's going through," Kipnis told reporters Tuesday night. "She's going to, unfortunately, be losing her hair soon here to chemo and so we all kind of wanted to join in, and it started with a couple and then spread throughout the whole clubhouse. ... It wasn't all in one day, just periodically, more guys were getting in on it and going through that."
Aviles went on the family emergency medical list earlier this month. Several days later, the Indians announced that the veteran infielder's daughter, Adriana, was being treated for leukemia at the Cleveland Clinic.
After missing a week and a half, Aviles rejoined the Indians on May 18. He has chosen not to speak about his daughter's condition with the media but said Wednesday he appreciated the team's show of support.
"It means a lot for me," he said. "It shows I'm kind of liked, or my daughter is, anyway. In all honesty, it's kind of cool when you have your whole team on your side. It goes without saying, everybody in here has families and they know how it is. It's a tough time, but to know that my team, the coaching staff, everybody, is on my family's side and my little girl's side, it helps out a lot and makes me feel good."
Aviles shaved his head soon after his daughter entered the hospital.
"She knows that Daddy did it," he said. "She thinks it's funny. She doesn't understand it, but she knows that Daddy did it."
Aviles' new look initially didn't get a positive reaction.
"At first, she didn't like the way my head looked," he said. "The more she looks at it, she's like, 'I like it. It looks cool.' I'm like, 'All of Daddy's friends did it, too.' Little by little, she'll understand."
Aviles, 34, entered Wednesday hitting .310 with three home runs and six RBIs. He is 10-of-19 since being activated.
Aviles says it's been an emotional time for his family. Adriana has a twin sister, Mayia. Aviles also has an older daughter, Kyla.
"It kills me not to be home the entire time," Aviles said. "At the same time, I know my wife is a great mom. She's doing a great job with her, so everything is good at home. The way I see it is, she's going to fight and I'll be right there with her. It's good to know that we have a lot of support on her side."
Indians manager Terry Francona is pleased with the support for Aviles and his family. Francona and bench coach Brad Mills have gone with the shaved-head look for several years.
"I know probably some people look at shaved heads as juvenile or whatever, but it's a bunch of guys that really care about their teammate," Francona said. "A lot of guys probably don't even know Adriana, but because it's Mikey's daughter she's important to all of us. I think it's a way to take something that's very serious, makes you step back and think.
"I guarantee you when she sees pictures of all these guys, she's going to smile."
Information from The Associated Press was used in this report.