PHOENIX -- D-backs pitcher Ian Kennedy and manager Kirk Gibson understand why fans booed Justin Upton on Wednesday night at Chase Field after the outfielder went 0-for-5, leaving him 1-for-18 in his past four games.

But they still feel sympathy for the face of the franchise, who both of them agree is working as diligently as possible to find his way out of the slump.

"It's tough, fans here take a little while to do that, they aren't quick to do that," Kennedy said of the booing. "But sometimes it's hard to watch your fellow teammate get booed. We know he's playing as hard as he can. He's come up in big situations a lot, it's not easy to produce every time. As a teammate, we feel for him."

On the season, Upton entered Thursday hitting .263 with seven homers and 34 RBIs. The batting average isn't too far off where he finished last season (.289), but the power and run production numbers are way down. In 2011, Upton hit 31 homers and drove in 88 runs.

The 24-year-old responded to the boos after Wednesday's game.

"To be honest, I don't care anything about what the fans think of me," Upton said. "My teammates, my coaches, they know I bust it every single day. I do everything to help this team.

"The fans can think whatever they want to think. They can call my lazy, I've heard that. They can call me washed up. Whatever they call me, at the end of the day, I'm thankful for every opportunity I get on the baseball field and I try my hardest every day."

Gibson said Thursday the connotation of Upton's words were different than how the actual context read.

"I think what he was saying was he knows he goes out and prepares for the game the same way either way," Gibson said. "Obviously he cares, if he didn't he wouldn't be working right now. He stays with it and plays the game very well."

Again, Gibson acknowledged that fans booing players when they are not performing well is part of the game, but he still hopes that it quiets down for Upton's good.

"I'll say this about the fans: Let's stop and think about it. Do we want him to do good? Would booing help motivate someone?" Gibson said. "We all understand why they do it, but [Upton] cares about everything he does. I've been booed several times. It's because they have high expectations."

Adapting to big leagues part of process for Bauer

PHOENIX -- For a 21-year-old, D-backs right-hander Trevor Bauer is set in his ways. He knows what has worked for him in the past, and he doesn't want to stray too far from that.

But the Major League level is different than anything the top prospect has faced, and D-backs manager Kirk Gibson predicts Bauer will adapt eventually, whether he knows it now or not.

"You live and you learn, he's going to change, we all change," Gibson said. "If he continues to get bad results, he's going to change. If not, he won't be here, no different than anybody else. It's a process. I used to stand with my hands low, I thought I was never going to change. But then I got tired of striking out, and all the sudden I put them higher. It's going to happen for everybody."

In his first two starts, Bauer surrendered nine runs (eight earned) on 11 hits and seven walks in 7 1/3 innings.

By his own admission, what didn't work for him was getting his breaking pitches over for strikes, so opposing hitters were sitting back and waiting for fastballs and changeups.

Bauer said he compounded the damage by throwing the fastballs low in the zone. Generally, pitchers don't try to hurl heaters for strikes up in the zone, but Bauer does not fit into that mold.

"Ninety-five percent of the hard-hit balls are pitches at the bottom of the strike zone," he said. "When I'm executing and throwing fastballs at the top of the zone, I've never been hit consistently. Sometimes people guess and hit a ball out, but that's not going to happen on a consistent basis."

Whether that plan works in the big leagues remains to be seen, but Bauer did agree that he needed to work with catcher Miguel Montero more to get a feel for each other.

Bauer shook off Montero's calls multiple times in his last start Tuesday against the Padres.

"We're going to have a meeting and discuss how he likes to call games and how I like to throw games and find some middle ground," Bauer said. "I haven't thrown to him very much. I throw drastically different than most people throw. We haven't had time to talk about it."

Whether Bauer could benefit from Montero's knowledge of hitters in the National League, the pitcher isn't sure of either.

"I don't throw to hitters' weaknesses, I throw to my strengths," Bauer said. "My approach is independent from who is at the plate. It'll be helpful to get his knowledge on what pitch the guy is looking for, though. He can see different things back there. Once we have a meeting and get on the same page, it'll be easier to know he's calling a pitch for a reason."

The rookie put some of the failures he's experienced on a nagging groin injury that forced him to leave his first outing in Atlanta early and also hampered him Tuesday.

But he said the groin was doing much better the last few days.

"It's frustrating more than anything, I hadn't felt my groin in more than a month before this," he said. "For me, I tend to focus on the frustration part and the negative part. I'm working on being more positive."

Even though it hasn't been smooth sailing for Bauer in his first two weeks of the Majors, he isn't down on himself at all. Instead, he still carries the same swagger with him that Gibson said is "what makes him good."

"I know when I execute my pitches and my game plan, I'll be effective no matter who I'm playing," he said. "I didn't execute last time, that happens. If there's ever a time when I execute my game plan a few times and I still get lit up, I'll make an adjustment on my game plan."

Saunders to throw Sunday in rookie league game

PHOENIX -- In preparation to return to the D-backs' rotation after the All-Star break, Joe Saunders will throw upward of 90 pitches Sunday in an Arizona Rookie League game at Salt River Fields.

The 31-year-old pitched a simulated game Tuesday at Chase Field and came out of it saying he felt ready to start right away for the D-backs, but the club insisted on him throwing again beforehand.

"It's very noble to think he can sit out for three weeks, throw one time, then be ready to throw 110 pitches," D-backs manager Kirk Gibson said. "But that's not smart. Could he do it? Yeah, but what about the next start? You have to be mindful of the future."

Saunders has been on the disabled list since June 23, retroactive to June 17, with shoulder inflammation. The lefty is 4-5 with a 3.44 ERA on the season

"Most important thing is he gets his pitch count up." Gibson said. "We talked about it yesterday, he gets it. We want Joe Saunders on the mound."