And it's pink.
Butera said he made a promise to 7-year-old Dagan Lingenfelter when the boy was in the hospital getting chemotherapy treatment for acute lymphoblastic leukemia in 2016. His promise: When Lingenfelter beat cancer, he could dye Butera's hair any color that he wanted.
"So, he comes in and says that when I kick cancer's butt, I can dye his hair any color he wanted, and we made a deal and we did that today," Dagan told reporters before Friday night's game.
According to The Kansas City Star, Lingenfelter's mother said her son's cancer has been in remission since March 2017.
The Royals posted a video on Twitter of Butera and Lingenfelter visiting a salon and both getting the tops of their locks colored. Lingenfelter was wearing a No. 9 "Butera" jersey, while Butera was sporting a No. 9 "Dagan is rad" jersey.
"He was in the hospital battling cancer and going through chemo," Butera said. "I made a promise to him, he had his hair dyed, that when he beats cancer he could dye my hair. So today, cancer-free, and we're dying some hair."