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Boston Red Sox manager Terry Francona (search) was taken to a hospital Wednesday with tightness in his chest and missed the start of his team's game against the New York Yankees.

He was resting comfortably in the hospital awaiting test results, the Red Sox said during the game.

Francona, who turns 46 on April 22, was not feeling well all morning, according to general manager Theo Epstein (search). Francona was taken by ambulance to New York Weill-Cornell Medical Center in Manhattan, where he has relationships with several doctors.

"He was taken to the hospital for precautionary tests," Epstein said. "He had all his faculties about him, he was just going for tests."

Bench coach Brad Mills (search) filled in for Francona against New York. Mills, friends with Francona since they were roommates and teammates at the University of Arizona, was with Francona at Yankee Stadium on Wednesday morning.

"He just felt a little tightness in his chest," Mills said. "He was a little concerned, there's no doubt. He told me, `Don't worry about me. I'm going to be OK.'"

Epstein spoke to Francona and said he was upbeat.

"He wishes he was at the ballpark," he said.

Before the game, Epstein also left the park and went to the hospital to see Francona.

Francona took the 8 a.m. team bus to Yankee Stadium and began his routine, even fulfilling media obligations despite not feeling well.

Epstein said the Yankees made their entire staff available to Francona. Epstein didn't know what type of tests Francona was having, but Red Sox team doctor Thomas Gill was monitoring his condition by phone from Boston, and team trainer Jim Rowe accompanied the manager to the hospital.

Epstein informed the team about Francona after the second Red Sox (search) bus arrived at the stadium around 10:30 a.m.

"It was scary because you're talking about real-life stuff, you're not talking about wins and losses," Boston first baseman Kevin Millar (search) said.

Francona, who led the Red Sox to their first World Series championship in 86 years in his first season as manager, had experienced chest pains before — a side effect of life-threatening blood clots that developed from a knee operation.

Ten days after knee surgery in 2002, he was in Seattle interviewing for the Mariners' managing job when he experienced severe chest pains.

Upon his return home, Francona said, doctors discovered a blood clot had gone to his lungs. He was given blood thinners and the problem was thought to be under control, but complications developed. He had staph infections in both knees, which required four more operations, he said, and then developed serious hemorrhaging in his leg that ultimately required an additional two operations.

He was sent home after Thanksgiving, but more clotting ensued and he was hospitalized until Christmas Eve. In all, he said, he underwent eight operations to deal with the problem. On more than one occasion, he said, the situation was life-threatening.

Francona played 10 years in the major leagues as a first baseman and outfielder. He had already had 11 knee operations when he went in for the arthroscopic procedure in November 2002.

Francona also managed the Philadelphia Phillies from 1997-2000.