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PHOENIX -- Tony La Russa caused some raised eyebrows last offseason when he said he would be "broken-hearted" if the Diamondbacks didn't finish 2015 with a winning record.

For a brief spell in August, it appeared as if major league baseball's youngest team was going to make good on La Russa's leap of faith, but Tuesday night's 6-2 loss to San Francisco left the D-backs with a 66-73 record and needing to go 16-7 over their final 23 games to top the .500 mark.

While it appears as if La Russa's heart will survive the late-season downturn, he acknowledged in an impromptu meeting with reporters that the final four weeks of the season will be critical to perceptions of how far the team has progressed following a 98-loss 2014 season.

"I can see the improvement, but at the same time if you put it against championship execution, we still have learning and growing to do," La Russa said. "I don't want to belabor we're the youngest club in baseball, but that's what we have, and we've competed.

"My biggest anxiety . . . is these last four weeks. What happens last is what's remembered most, so for all of us, I think this club deserves to get enough wins to represent how competitive they've been all year long."

La Russa said he's been pleased with the organizational depth that has begun to surface at the major-league level this season and looks forward to some healthy competition for jobs next spring, as well as the opportunity for general manager Dave Stewart to be active in the market this off-season.

"I think it's a good position to be in," he said. "I know Stew's getting calls, we do have some depth. But there isn't anybody in any of those mixes that we don't foresee as a major leaguer for us."

Just as important, he said, is the understanding that trades and free-agent signings are not the only answer.

"An important part of it, because you can't always get what you want, is to concentrate on what you have. An important priority will be to continue the improvement of our pitchers and our every-day guys, because we can win more games with the same guys."

La Russa pointed to the emergence of outfielders of A.J. Pollock, David Peralta and Ender Inciarte -- which, in turn, has limted the at-bats for $68 million off-season acquisition Yasmany Tomas.

"You've got right now three guys who are as good a solid threesome as anybody's three," he said. "So whether you are Tomas or you are (Socrates) Brito or (Peter) O'Brien, it's a tall order, but that brings out the best in you.

"You can never have enough good players. There's always a way that it works out.

He also acknowledged the crowd of young middle infielders that includes Nick Ahmed, Chris Owings, Phil Gosselin and Brandon Drury. And that doesn't include No. 1 draft pick Dansby Swanson, who has only a couple months of pro ball under his belt.

"I think it is just the beginning of the sorting," he said. "The process has just begun. (I) hope they are all friends."

La Russa revealed no disappointment with the progress of Tomas, who played well initially but has struggled late in the season as the at-bats have become more inconsistent. His average is at .282 after Tuesday night's 0-for-3 performance.

"I think that it's a testament to how much talent he has that he has survived it. He doesn't know these pitchers, hasn't had a lot of at bats.

"He's going to have an interesting winter. He needs to make sure that he gets himself fighting trim. It's going to be his first winter in the States, and you have to have a lot of discipline to eat right, work out right. But when you have talent like he has, he has a bat that is going to force its way into the lineup."

Tomas' playing time has been inversely impacted by the ascendance of Peralta, just a couple of seasons removed from washing out as a minor-league pitcher. It's a story that's captivated a lot of the baseball-watching public, even a lifer like La Russa.

"He plays with as much intensity as anybody that I have experienced," La Russa said. "He comes out there and he gives you everything he has got every inning, every at-bat, defensively, on the bases. That shows me a very strong mind. Sets a great example for our club.

"It's an amazing story. I have never seen him take an inning, an at-bat, off for almost two years, and I don't care how good you do or how bad you do, nothing deters him from getting ready to play. I don't think he'll ever lose that, either. I think that's who he is. "

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