Standout center fielder Carlos Beltran was traded from Kansas City to the Houston Astros on Thursday night as part of a three-way deal that also sent reliever Octavio Dotel to Oakland.

The last-place Royals wound up with three prospects: highly touted third baseman Mark Teahen and right-hander Mike Wood from Oakland, and catcher John Buck from the Astros.

“This is obviously huge for our organization,” Astros general manager Gerry Hunsicker said. “Carlos Beltran is one of the most exciting, complete players in our game today.

“He’s the prototype we’ve been looking for for a long time. He’s going to be a very exciting force for us in the middle of our lineup.”

Beltran can become a free agent this fall — but for now, he joined a team clearly going all out this year to win its first World Series.

The Astros spent millions last offseason to bring pitchers Roger Clemens and Andy Pettitte to Houston. Clemens, who already ended one brief retirement, agreed only to a one-year deal, while longtime stars Jeff Bagwell and Craig Biggio are nearing the end of their careers.

Last week, the Astros traded right fielder Richard Hidalgo to the New York Mets for reliever David Weathers and a minor-league pitcher. This time, Houston pulled off a much bigger deal.

“When you have a chance to get an All-Star like Beltran, you do it, then you worry about filling in holes. He significantly makes us better, he is an impact player and will have an effect on our ballclub,” Hunsicker said.

The multitalented Beltran is hitting .278 with 15 homers, 51 RBIs and 14 steals.

“I feel pretty good about this. Obviously, it’s bittersweet,” Royals general manager Allard Baird said.

“It was obvious we were not going to be able to sign Carlos. But I think we’ve helped this club and gotten some players that should have very productive major league careers,” he said. “I’m going to bring Buck and Wood to the majors right away.”

The 27-year-old Beltran, the biggest prize on the trade market, is making $9 million this season. He’s represented by Scott Boras, who usually does not have his players re-sign before testing the free-agent market.

“It’s been a crazy day, with a lot of ups and downs. It was a very challenging day for all of us,” Hunsicker said.

As part of the trade, the A’s also received cash from Kansas City, an amount under $1 million. Oakland was looking for help at the back of the bullpen.

“At the time I went to bed it didn’t look like this would get done,” A’s general manager Billy Beane said. “There were other possibilities.”