Boston ? Fans filed into Fenway Park early Monday for the start of a daylong tribute to Hall of Famer Ted Williams.

The stadium gates were opened for four hours to allow fans to walk on the field and remember Williams, who died July 5. A memorial service opened to ticketholders only was scheduled for Monday night.

Billboards hung in the netting above the Green Monster in left field: “There goes the greatest hitter who ever lived,” read one. “Ted Williams: An American Hero, 1918-2002,” read another.

Only a handful of fans were waiting when the gates opened, but by midmorning 1,500 fans had entered the ballpark. John Zellmann, 38, and his 17-year-old son, Derrick, took the day off to pay tribute to the Splendid Splinter.

“For me, it’s just the way he played the game. He’s a symbol of the Red Sox,” John Zellmann said.

Inside the ballpark, each base marked a milestone of Williams’ career. At first, a “521” _ the number of home runs he hit. At second, “USMC,” marking his service in two wars as a Marine Corps pilot. And at third, a “.406” _ his batting average in 1941. He was the last player to hit over .400.

Near the scoreboard, large black and white photographs highlighted three aspects of Williams life: baseball, military service and his work for the cancer research charity, the Jimmy Fund. Those themes were to be featured prominently at the evening service, “Ted Williams: A Celebration of an American Hero.”

Anne and Stuart Eckman, of Haverhill, were among the first fans to walk by the display at the left field wall. Stuart said he had seen Williams play, and respected him as a ballplayer and for his military service.

“We won’t see his likes again,” he said.

The proceeds from the evening memorial service were to go to the Jimmy Fund. Only 18,000 of the 33,000 tickets for the service had been sold. And Williams’ three children were not expected to attend.

Since Williams’ death, his children have been fighting over what to do with his remains. His son, John Henry Williams, wants his father’s body to stay frozen in a cryonics lab in Arizona; his oldest daughter, Bobby-Jo Williams Ferrell, said her father wanted to be cremated. The dispute is pending in probate court in Florida.

Former Ohio Sen. John Glenn, who flew combat missions in Korea with Williams, eight-time batting champion Tony Gwynn, Red Sox shortstop Nomar Garciaparra and former Boston players Dom DiMaggio, Carl Yastrzemski and Johnny Pesky are expected to speak at the memorial.

“Ted meant an awful lot to us,” Pesky said. “There’s a lot of people who had a lot of admiration for Ted, the greatest Red Sox player since Babe Ruth.”

Pesky said he knows it will be tough to get through the service without breaking down.

“I hope I don’t get emotional,” he said. “Ted wouldn’t like it if I got that way.”