New York Yankees slugger Jason Giambi learned Thursday that he will be shelved at least three weeks because of torn tissue in the arch of his left foot.

Giambi, 36, will be placed on the disabled list prior to Friday's series opener against the Boston Red Sox at Fenway Park.

Jason Giambi has had foot problems since returning to the field from DH.
(Jim McIsaac/Getty Images)

"He will be re-evaluated in three weeks," Yankees spokesman Jason Zillo said.

Giambi was examined by Dr. William Hamilton in New York and told that the foot will have to be placed in a walking boot.

He originally was diagnosed with a bone spur, and switched to cletes with orthotics that helped relieve the pain temporarily.

"I would say it is a severe injury," said Yankees general manager Brian Cashman, hinting that Giambi might sit out six weeks.

Asked if Giambi could be sidelined the rest of the season, Cashman replied: "That I don't know. Ultimately, it simply will be ready when it's healed

"Right now, I cannot tell you how long that's going to take."
 
Giambi is hitting .262 with seven home runs, 23 runs batted in and 19 runs scored in 45 games this season, his sixth with New York.

But he began struggling when shifted from designated hitter to first base, averaging .117 with three HRs and six RBIs in May.

Giambi realized something was seriously wrong when he homered in the seventh inning of Tuesday's 3-2 loss to the Toronto Blue Jays at the Rogers Centre.

"Rounding the bases, he felt a pop," Cashman said. "There wasn't a tear before.

"Now there is."
 
Giambi was named the American League's most valuable player in 2000 and AL comeback player of the year in 2005.

The five-time all-star is a career .291 hitter with 357 HRs, 1,167 RBIs and 1,036 runs in 1,667 games over 13 MLB seasons for the Oakland Athletics and Yankees.

Giambi is in the sixth year of a seven-year, $120-million US contract he signed with New York on Dec. 13, 2001.

With files from the Associated Press