TAMPA, Fla. -- After arguably the most celebrated arrival at Yankees camp in more than a decade, all eyes were on Gerrit Cole on Wednesday at George M. Steinbrenner Field as the ace right-hander took the mound for his first bullpen session in pinstripes.

With a phalanx of photographers capturing his every movement, Cole warmed up by tossing across the right-field grass, then he entered the bullpen "six-pack," where he threw 25 pitches -- fastballs and changeups -- to catcher Gary Sánchez.

“It was good,” Sánchez said through an interpreter. “It was only fastballs and changeups today, so that makes it easier. It's the first day. Many more coming.”

Cole is the only member of the 40-man roster who was not in the organization last season, having agreed to a nine-year, $324 million contract in December. Managing general partner Hal Steinbrenner expects Cole “to be a game-changer for us,” heading a rotation that projects to also feature Luis Severino, Masahiro Tanaka and J.A. Happ, with a competition for the No. 5 slot.

“He's arguably the game's best pitcher,” manager Aaron Boone said. “We're adding a bona fide ace to already what we feel like is a really good rotation. We just feel like he's that anchor at the top. … It’s exciting to see him come in here, knowing this is where he absolutely wants to be and feels like there was a little bit of destiny to get here.”

Following the bullpen session, Cole spoke animatedly for more than 10 minutes with a group that included Boone, pitching coach Matt Blake and bullpen coach Mike Harkey.

“It confirmed all those things we saw from him this winter, when we got to meet with him,” Boone said. “Just how specific he is about everything he's doing and that understanding of every pitch he makes, what it's doing, what it needs to look like. His attention to detail is special, so it was a good first day for him to get out there and get on the mound in a good uniform.”

Boone senses Cole will be easy to converse with, especially when the topic revolves around the art of pitching.

“We were talking everything from how he's shaping his changeup and how he wants to throw it, what his arm action should be doing and where his misses are,” Boone said. “It's just a really good baseball conversation with a great player that understands who he is really well. … He's one of those guys, like a lot of great players, that expects a lot of themselves. He works really hard to continue to be great at his craft.”

Sánchez is happy to avoid the challenge of facing Cole, who went 20-5 with an American League-best 2.50 ERA and a Major League-leading 326 strikeouts last season for the Astros.

“Facing a guy like him, he throws hard,” Sánchez said. “You have to look for a pitch and try not to miss that one pitch. You only get one chance. It's tough because you don't have a lot of time to put the ball in play. All the pitches he has, you just try not to miss the one that you get. That's what makes him very hard to hit against.”