PEORIA, Ariz. -- A Spring Training game can be tricky for veteran starting pitchers.

There's a need to build up their pitch count and a desire to fine-tune certain pitches in preparation for the long season ahead. Although the stat line ultimately doesn't mean anything, their inner competitor wants to put up a zero in every inning they pitch.

Zac Gallen didn't accomplish the latter on Tuesday. He allowed two runs on five hits and a walk over 2 2/3 innings in Arizona's 2-2 tie against San Diego. However, the D-backs ace was satisfied with his day's work.

"I felt OK; just obviously working on stuff, a lot of fastball curveball, trying to get those two pitches right," Gallen said. "Obviously, it's a little different when you're facing a team in your division. You want to get the work in, but you don't want to give away too much of your hand."

The D-backs won't see the Padres in a meaningful game until the first week of May, so manager Torey Lovullo wasn't worried about sending his ace out against a division foe in an exhibition game. It helped that Gallen focused on his fastball and curveball, throwing them on all but four of his 45 pitches.

"He's working really with two pitches and didn't give the full arsenal; it's just an experienced mindset," Lovullo said. "He doesn't want to show too much of his hand. It just goes to show you how intelligent and how big of a picture he sees."

"You're going to have to face the division teams," Gallen said. "You can't really just throw back-field games all season. You have to get ready to go. I have to figure out different ways to get guys out, use Spring Training as a learning experience."

Gallen used his fastball/curveball on 72 percent of his pitches in 2023, but he has been fine-tuning them as he readies for 2024. He "wasn't too thrilled" with his fastball command on Tuesday, but the curveball worked to his liking.

Fernando Tatis Jr. and Manny Machado had singles against Gallen in the first, but he escaped without allowing a run. The right-hander got two quick outs in the second, then got ahead of Kyle Higashioka before walking him. Jackson Merrill, the Padres' No. 2 prospect and No. 12 on MLB Pipeline's Top 100 list, followed with a home run, accounting for both of San Diego's runs.

"The homer I'm not necessarily mad about," he said. "I was in the strike zone, didn't make a great pitch and the kid made a good swing. The two-strike, two-out walk, that's something that has got to be addressed. The hits and runs and things like that, it's going to happen. It is what it is. The other things that I can control is what I look at."

Gallen knows he'll be working with his complete arsenal the next time he sees the Padres. While some pitchers don't like facing a division opponent in Spring Training, he believes there is a benefit to pitching in Cactus League games rather than simulating one at the team's complex.

"There's a competitiveness that comes out in Spring Training that you can't really replicate on the back fields facing your teammates," Gallen said. "It gives you a test of how your stuff is standing up right now, to see how close you are in terms of stuff and feel and what the hitters are giving you in that type of environment.

"I can go out there and say I felt really great about the curveball and we can look at the metrics and all that stuff, then if I'm backing up third base every time I throw it, it's like, 'OK, maybe it's not the best pitch.' I felt like I got some pretty solid swings from my part, takes and offers and things like that where I was like, 'OK, it's all kind of coming together.'"