The young Yankees outfielder is giving up the number he did have, No. 30, to David Robertson, who wore the digits during his first stint with the Yankees, because, he said, it's the right thing to do.
Robertson was acquired Tuesday along with power-hitting infielder Todd Frazier (no relation) and reliever Tommy Kahnle from the Chicago White Sox in exchange for reliever Tyler Clippard and three prospects.
"I've been here like five minutes," Frazier said.
Frazier, 22, said he did not take No. 77 because of Mantle, but he did want a number with seven it. He had not previously worn No. 7 at any level.
"I wanted a number with seven in it," Frazier said. "There's not many numbers available, and [Aaron] Judge wears 99, so maybe go with something like 77 and hope someone else picks 88 in the outfield."
Earlier in the season, a WFAN radio report claimed that Frazier asked if the Yankees ever unretired numbers because he wanted No. 7. The story was later retracted, and the Yankees' analyst, Suzyn Waldman, apologized to Frazier.
Frazier said there is no significance as to why he wants No. 7.
"None," Frazier said. "I've never worn a single-digit seven. I've worn 17. I wore 75 in spring training."
Fellow outfield prospect Dustin Fowler wore 77, and Frazier said he liked the way it looked.
During spring training, Frazier made headlines because the length of his red curls flirted with violating the team's policy on hair. Yankees manager Joe Girardi eventually recommended Frazier shave it all off, and Frazier did.
Frazier entered Wednesday batting .279 with three home runs and eight RBIs in 12 games.