"It'll be exciting," Cubs first baseman Anthony Rizzo said. "He was here for a long time and did a lot of good things here. Obviously, he got traded to a great team, the Yankees, but part of him was part of that [Cubs] team last year that won a World Series. I'm sure he felt that."
It may be bittersweet for Castro to watch his current Yankees teammate Aroldis Chapman receive a ring on the field Friday. The Cubs acquired Chapman last July, and the closer was a big reason why they reached the World Series.
"I'm sure it will be [bittersweet], but like every other Cub who has put on this uniform, that championship is for them," Rizzo said. "Starlin is closer to that goal than a lot of other alumni."
One of the toughest decisions Cubs manager Joe Maddon made in his first year with the team in 2015 was to move Castro from shortstop to second base to make room for Addison Russell.
"I remember talking to him in the manager's office sitting across from me," Maddon said of their conversation in August 2015. "He didn't blanch, he didn't make an excuse, he didn't cry or scream, 'What are you doing?' I said, 'You're not going to play for a couple days. I want you to start working at second base.' Not a whimper. It was outstanding on his part.
"He's taken it and run with it," Maddon said. "He's in a really good position with a very good ballclub. I know he can handle the big lights in New York, I know he can do that. I cannot be happier for his success."
Castro made a splash in his big league debut on May 7, 2010, with the Cubs, when he homered in his first at-bat and finished with six RBIs against the Reds. A three-time All-Star at shortstop, he had to deal with a lot of turnover as the Cubs changed managers and hitting coaches during his tenure.
"A young guy like that, probably his best resource was that he was so good, he was immune to all this in some ways," Maddon said.
The constant was Rizzo, who joined the Cubs in 2012.
"There were so many guys coming in and out, you'd start Spring Training with one group and end with a completely different group," Rizzo said. "We were always the two here. And we played every day. Playing every day, you form a bond with guys. Whether you like them off the field or not, on the field and in the clubhouse, you form this bond. Castro and I had a good one, on and off the field."
Maddon was eager to see Castro, who was traded to the Yankees for reliever Adam Warren in December 2015.
"He was a great teammate here, and I thought I had a great relationship here with him," Maddon said. "He never made an excuse. When anything went poorly, he stood tall. I'm very happy for his success and looking forward to saying hello to him."
Carrie Muskat has covered the Cubs since 1987, and for MLB.com since 2001. She writes a blog, Muskat Ramblings. You can follow her on Twitter @CarrieMuskat and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.