That would be 2002 and '03. Yankees manager Joe Girardi has noticed a more lively Giambi, one who gives him optimism of being a fixture in the Yankees' lineup this season.
Forget that Giambi hasn't played more than 139 games in a season since 2003 and missed two months last season with a torn left plantar fascia.
"Jason is a force," Girardi said before Saturday's spring finale against the Florida Marlins at Dolphin Stadium. "He's a dangerous bat when he's healthy. I'm counting on him. I expect him to be ready every day."
Giambi feels similarly. He's tired of being slowed by injuries.
"It's like a second wind," he said. "I used to always chalk it up to my legs being older and beat up. But I feel great now."
Giambi solved his foot problem with surgery and found that orthotic inserts made it easier to keep his feet healthy. He did a lot of running in the offseason.
"I'm enjoying every minute of it so far," Giambi said. "The biggest thing is I'm having a great time. I'm having a great spring, and hopefully, that will carry over into a great season."
With a 2-for-3 game on Saturday, Giambi finished the spring hitting a gaudy .413 batting average, with two home runs and eight RBIs in 46 at-bats.
"My body feels great," Giambi said. "I'm excited about the way I'm swinging the bat. Everything has been going well."
He attributes a big part of his rejuvenation to rehabilitating his feet so that he can run without pain.
"I learned a lot about the problem that I had," he said, "so I cleaned that up. My legs feel great."
A healthy Giambi could go a long way toward giving the Yankees a more fearsome lineup. Girardi expects Giambi to be the team's regular first baseman and log some time as a designated hitter.
Last season, Giambi started 56 games at DH and only 18 at first base. Four Yankees played more than 18 games there, including since-departed utility man Miguel Cairo with 22.
Giambi has always been able to hit for power. He has 364 career home runs and hit 41 in each of his first two Yankees seasons, with 32 in 2005 and 27 in '96.
Giambi knows his track record indicates that when he plays, he produces. As another season is nearing, he feels he is as ready now as he's been in the past five seasons.
Charlie Nobles is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.