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2/17/2013 4:27 P.M. ET

Trade rumors behind him, Kubel's focus on field

After late-season struggles, D-backs outfielder determined to produce all year

SCOTTSDALE, Ariz. -- Based on the hot stove chatter, the fact that Jason Kubel was in D-backs camp when it opened this past week was a bit of a surprise.

The outfielder's name had been mentioned in trade talks throughout the winter, and it wasn't until Arizona finally dealt outfielder Justin Upton to Atlanta late last month that Kubel's return to the desert was assured.

"It's all talk, but when it's all you hear, it's pretty hard not to think about it," Kubel said. "I was just prepared for pretty much anything. I just would have dealt with it whatever had happened. If it was just me, it would be no big deal, but I've got to take the family around and we already had a place here set up the way we needed it, so it would have been a little tough. But we would have made it work."

Kubel signed a two-year contract before last season worth $16 million. He will make $7.5 million this year, and there is a mutual option for '14 for $7.5 million with a $1 million buyout.

Kubel was productive in 2012, hitting .253 with 30 homers and 90 RBIs, while his on-base plus slugging was a more than respectable .833.

Yet it was almost as if Kubel had two different seasons.

Through the end of July, he was hitting .290 and had an OPS of .928.

From Aug. 1 until the end of the season, he hit just .171 with a .624 OPS.

"I can't put a finger on it," Kubel said of the reason for the dramatic dropoff. "I just want to work a little harder this year to make sure that it doesn't happen again."

There has been much talk within the organization about why Kubel struggled down the stretch. One reason could be that unlike in the American League, Kubel was not able to use the designated hitter spot to get a break from playing the outfield.

"Your theory is as good as mine," D-backs manager Kirk Gibson said. "He came from the American League, it's a different game. Came over here and fit in very well and was on fire, hit all the home runs and then maybe got a little tired and started not to hit home runs and you start pressing. It happens. It could happen to anybody.

"I know if you talk to him, he wasn't happy about it and that was a point of contention with him all offseason. I know he's tried to come in a little differently this year with a little different mindset, has a better idea what it takes to play a lot over here in the National League without the luxury of the DH. He looks good."

The biggest difference for Kubel this offseason was not in determination, but in health.

The left ankle injury that he battled during the 2011 season lasted into the winter and prevented him from running.

"I was able to do a lot more work this offseason," Kubel said. "Last year I had a foot injury so I wasn't really cleared to work on my feet, so I couldn't do cardio. I wasn't able to do that until the middle of January. This year I was able to get going in early November, so I feel a ton better this year than I did last year."

In addition to being in better condition, Kubel should also benefit from the D-backs' outfield situation.

With four outfielders who could start on any given day in Kubel, Adam Eaton, Gerardo Parra and Cody Ross, Gibson has said he will likely use a rotation that gets each of the outfielders 500 or so at-bats. That extra rest could help keep Kubel fresher down the stretch.

"I don't know," Kubel said when asked if he was fatigued last season. "I don't feel like it was, but I can't really think of any other reasons for why I would just all of a sudden struggle. I think with the work put in and not missing any time I think I'll be able to get after it like normal now. We'll see how it all works out. We've got plenty guys who can go out there and do it. That's a good thing to have."

Steve Gilbert is a reporter for MLB.com. Follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.