"The Rockies lost an alarming 30 one-run games in 2010, partly because Jason Giambi, at 39, was going through his rookie season as a late-inning pinch hitter.

Being a designated hitter is one thing. But Giambi, the proud owner of more than 8,000 plate appearances in the big leagues, discovered that nothing could have prepared him for the job he took on last year.

"It's different than DHing," Giambi said. "Coming off the bench here or there is definitely the toughest role in the game. After last year, I have a lot more respect for guys who can get it done, and do it well."

Giambi is, to use Rockies manager Jim Tracy's term, the last bullet. He pinch hits with the game hanging in the balance. And he doesn't do it against just any pitcher. It's almost always a hard-throwing closer, and it's often a left-hander.

A year later, Giambi plans on putting a dent in all those one-run losses. He believes he can be a force, a hitter who makes the difference in close games. And there are two reasons to think he could be right.

For one thing, he's familiar not only with the role, but with the pitchers he'll typically be facing. For another, his swing in the latter stages of spring training is better than at any point early in the 2010 season.

"His swing right now . . . let's put it this way: It's months ahead of where it was at the early stages of last year," Tracy said. "That's how good he looks at the plate."

Giambi and Todd Helton are at the top of the list of Rockies players who've benefited from the move to Scottsdale from Tucson. Each is getting at-bats against major-league pitchers instead of avoiding five-hour bus trips and taking cuts against minor-leaguers."