But he's not immune to the first-day jitters that come with suiting up for a new team and pitching in a historic ballpark for the first time.
"My heart is going to be pumping," Galarraga admitted about his upcoming Wednesday start, when he makes his debut with the D-backs and faces the Cubs at Wrigley Field.
Galarraga will be facing Chicago for just the second time in his career, and he'll be making his first start since coming over from the Tigers in an offseason trade for a pair of Minor Leaguers.
Galarraga, who beat out Aaron Heilman for the fifth spot in the rotation this spring, went 4-9 with a 4.49 ERA in 25 games (24 starts) in Detroit last season -- one of which, of course, was a would-be perfect game.
The right-hander was pushed back one day after snow postponed Sunday's game in Colorado. D-backs skipper Kirk Gibson didn't want to skip Galarraga's turn altogether.
"I've been watching all his bullpens, and he's been throwing the ball better and better," Gibson said. "I think it's important to have Armando throw right now."
Right now will likely coincide with Geovany Soto's return to the Cubs lineup after a one-game hiatus.
Cubs manager Mike Quade decided to rest his catcher for Tuesday's afternoon game after a good early start Soto badly needed. In his first four contests, the 28-year-old has recorded two multi-hit games, including a 2-for-3, two-double game against Arizona on Monday.
Perhaps most importantly, Soto's arm has looked good despite shoulder surgery that limited him to 105 games in 2010. So far, he has thrown out two of six would-be basestealers.
"I've never seen him throw better," Quade, in his first full season as Cubs skipper, said prior to Tuesday's 6-5 win over the D-backs. "Don't rule out the fact he's blocking and doing stuff there. It's one thing to throw a guy out on a steal, but when you have to block a ball, find it and make a throw, that's a big play, too."
Soto was the National League's Rookie of the Year in 2008, then was limited to 102 and 105 games, respectively, the next two seasons. Last year, he finished hitting .280 with a .393 on-base percentage, but missed 16 games in August with a sprained right shoulder, then was shut down the rest of the year on Sept. 19 because of eventual shoulder surgery.
On Wednesday, he's expected to be behind the plate when Ryan Dempster takes on Galarraga.
"He's awesome," Cubs starter Randy Wells said of Soto. "Anybody who knows Geo knows he's constantly talking, chatting, doing something. You always feel like he's in the game and you always feel like he's out there with your best interests in mind."
D-backs: Losing streak to Cubs continues
With Tuesday's loss, Arizona has now dropped seven straight games to the Cubs, with its last win coming on April 29 of last season. The club has also lost five in a row at Wrigley Field. During their seven-game losing streak, the D-backs have been outscored 57-31.
Cubs: Pena expected back soon
Carlos Pena (mild right thumb sprain) wanted to start at first base on Tuesday, but Quade opted for the precautionary route and went with youngster Tyler Colvin, who responded with a two-run homer and three RBIs in his first career start at the position. Pena could be back in the lineup as soon as Wednesday.
Cubs pitcher Andrew Cashner was pulled from Tuesday's start after 5 1/3 innings because of tightness in his right shoulder. He had an MRI on Tuesday afternoon. ... Eighteen players on the D-backs' Opening Day roster this season were not on the Opening Day roster in 2010. ... Arizona has the hardest schedule to start the season in the big leagues, as 27 of its first 37 games are against clubs that finished the 2010 season at .500 or better. ... After appearing in three of the first four games, closer Carlos Marmol and setup man Kerry Wood were given a day off on Monday. ... Dempster has a 6.07 ERA in 17 career games (13 starts) against the D-backs.