Santana enjoyed his season here, enjoyed his teammates, and performed admirably (9-10, 211 innings, 3.24 ERA).
That will be the only difficult part, he said -- pitching against his former friends on the Royals.
"It's not easy because I used to play with these guys," Santana said. "But at the same time, you just have to not think about [who is at the plate] and go out and perform. It's a game."
As Santana waved at several Royals who were stretching before Saturday's game, his face broke into a wide smile. He hadn't had a chance yet to chat with his former teammates.
"Not yet. I just got here," he said. "I'm just happy to be here."
That he is wearing a Twins uniform instead of a Royals uniform wasn't from lack of effort by the Royals' front office. Two years ago, the Royals offered him the $14.1 million qualifying offer, but hoped to negotiate a longer deal. The two sides remained apart on the finances, however.
And the Royals had interest again last offseason but weren't interested in going the four-year, $55 million route the Twins did to lure Santana.
Instead, the Royals were more than content to land right-hander Edinson Volquez, who is 8-4 with a 3.48 ERA and a team-high 95 2/3 innings. Volquez signed a two-year, guaranteed $20 million deal with a club option ($10 million) for 2017.
And the Twins finally will get a chance to see what they have in Santana on Sunday.
"I'm back and I can't wait to pitch," he said. "What happened is in the past and it's time to go forward."
Jeffrey Flanagan is a reporter for MLB.com. Follow him on Twitter at @FlannyMLB. This story was not subject to the approval of Major League Baseball or its clubs.