CHICAGO -- After finishing the first half on a strong note, it seemed odd that D-backs outfielder Justin Upton would have to answer questions about possibly being traded.

But rumors continue to swirl around baseball that Upton could find himself wearing a different uniform by the July 31 non-waiver Trade Deadline.

Arizona general manager Kevin Towers said that he is not shopping Upton, but he did admit to being open to listening to offers for the 24-year-old. D-backs managing general partner Ken Kendrick referred to Upton as an "enigma" in a radio interview last month.

"I don't know anything," Upton said of the rumors. "I haven't been keeping up with it. I'm here to play baseball for the Arizona Diamondbacks, as of now."

It is the "as of now" part that will keep the rumors swirling.

Upton spent the break with his family in Phoenix and tried to do his best to not look into the trade rumors.

"It's hard to tune it out," Upton said. "You hear everything, obviously from you guys when you ask me questions or things like that. Other than that, I try to focus on today. Today I'm in a Sedona red uniform and I'm prepared to do what I've got to do."

Upton is owed $41.9 million through the 2015 season, and when he signed his extension in the spring of 2010, the idea of trading a young star in the making seemed out of the question.

However, after Towers took over as GM in September, he made it known in November that Upton was available. At the time, no team could meet the D-backs' asking price. Whether they can now remains open for debate.

Upton has a limited no-trade clause that includes four teams. In 2010, the teams were the Indians, A's, Royals and Tigers. Three of those four have changed since then, but what the exact teams are has not been stated publicly.

"I've been through it before," Upton said. "It does nobody any good, our side or their side, to worry about it. If it's something that happens, it happens. If not, I'm going to come here and be the same guy I have been in the past and now towards my teammates and giving my effort on the field. I'm going to continue to do that. I enjoy playing in Arizona."

Upton finished the second half with an impressive four-game series against the Dodgers in which he hit .467 with a 1.367 OPS (on-base plus slugging percentage). Overall, he is hitting .273 with seven homers and 37 RBIs.

D-backs manager Kirk Gibson said he is not worried about the rumors affecting Upton's performance.

"I think the best thing for Justin is to play," Gibson said. "He's played well for us. I've been one of the guys that's stuck up for the way he's played, the energy, even though he hasn't lived up to the expectations [that] everybody else has put on him. That's always a dangerous thing; that's hard. I think he's played with a great energy. His work ethic has been exceptional. I got no problem with that, and he's played well for us and he's been a pretty good catalyst for us as of late."

There has been speculation as to why the D-backs would even entertain trade offers for such a young and prodigiously talented player.

"There's always a reason behind everything," Upton said. "Obviously I don't know what that is. I can only do what I can do. I think baseball is one of those businesses where it's kind of, 'What are you doing for me now? And do I believe you can do it for me in the future?' I think that's kind of where we're at right now. I don't know what they're thinking. The only thing I can do is come in here and do what I can do. They're the ones who make the decisions."