BOSTON - Terry Francona sat in Fenway Park’s quiet visitors clubhouse, a room where Johan Santana probably won’t show up this year unless the Red Sox and Mets meet in the World Series.

No wonder Boston’s manager smiled.

Francona is happy that one of baseball’s best pitchers is headed out of the American League.

“That ain’t bad. I wish every pitcher would go to the National League,” he said Friday in an interview with The Associated Press. “I can’t lie about it. You don’t want to face him five times.”

That might have happened if Minnesota had traded the two-time Cy Young Award winner to the New York Yankees. They face the Red Sox 18 times this year.

Boston also was involved in talks to obtain the 28-year-old left-hander. But the New York Mets reached an agreement Tuesday to acquire Santana from the Twins for four prospects, leaving the Red Sox with promising youngsters they might have had to part with reluctantly to get him.

Santana would have been eligible for free agency after this season, but he agreed with the Mets on a $150.75 million, seven-year contract Friday. The pitcher was scheduled to take a physical Saturday morning before the deal could be completed.

Even without Santana, the Red Sox have a versatile rotation — 40-plus right-handers Curt Schilling and Tim Wakefield, 27-year-olds Josh Beckett and Daisuke Matsuzaka, and 23-year-old budding stars Jon Lester and Clay Buchholz.

The rotation is so deep that Buchholz might start the season in the minors, even though he pitched a no-hitter in his second major league start last season.

“I’m happy with our roster,” Francona said. “Our youth is exciting to me. To come through our organization, they know how we feel about things. Every kid that comes through, they know how to play and they know how to act, and that’s important. They integrate themselves in the clubhouse and at work and there’s a lot of people in player development that need a pat on the back for that.”

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In the past several years, the Red Sox have improved their farm system from one of the weaker ones in baseball to one of the best. It produced 2007 AL Rookie of the Year Dustin Pedroia, center fielder Jacoby Ellsbury and All-Star closer Jonathan Papelbon, who was on the mound for the last out of Boston’s World Series sweep over Colorado last year.

And there’s Lester.

In October 2006, the lefty was undergoing chemotherapy for anaplastic large cell lymphoma. In December of that year, doctors pronounced him cancer-free. And last October he started the final game of the World Series, pitching 5 2-3 innings of shutout ball and getting the victory in Boston’s 4-3 win.

Despite that, he was a key bargaining chip in Boston’s pursuit of Santana.

“I’m excited,” Francona said in a clubhouse cluttered with cartons, exercise equipment and couches. “We’ve grown very close to him. We’ve been through a lot with him. Any player who comes through the system, you’re going to (get close) but, again, this is a little special. I think he wants to be here and I think we’re excited that he is here.”

For a long time, it seemed Lester might be leading Minnesota’s rotation instead of filling out Boston’s.

He visited Boston twice this offseason and talked with his manager.