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8/12/2013 10:23 P.M. ET

Arenado delivering on offense in rookie year

DENVER -- It was another big moment, rookie third baseman Nolan Arenado shirking any pressure or anxiety to drive in the winning run in Sunday's 3-2 victory over the Pirates.

It was Arenado's 10th go-ahead RBI and seventh to decide the game, impressive numbers for a 22-year-old who broke into the big leagues less than four months ago. Arenado has drawn much acclaim for his stellar glove work at third base, quickly becoming a highlight-reel staple.

But Rockies manager Walt Weiss sees a valuable trait in his rookie on the offensive side, an ability to shed the unavoidable fear of the moment and drive in runs.

"In general, when you get those high pressure at-bats, there's going to be some emotion attached to it," Weiss said." There's going to be some adrenaline, there's going to be maybe some fear.

"I think the guys that perform well in those situations consistently -- guys that are tagged as clutch players -- those guys can harness those emotions and that adrenaline and use it to focus, as opposed to the adrenaline getting them away from their focus. When you talk about clutch players, that's what you're able to do."

On Sunday, Arenado stepped into the batter's box in the seventh inning against Pirates reliever Bryan Morris with a detailed strategy, smacking the second pitch he saw into right field for a double that scored Wilin Rosario from first.

"I knew he had a cutter and a slider," Arenado said after the game. "I was looking for cutter or slider middle-away. He threw me a first-pitch fastball in. If he would have thrown it again, I could've been jammed or not swung. Luckily it was a cutter right over the plate, and I was able to put a good swing on it."

Adding another layer of difficulty to such situations is that the opposing club often selects a certain pitcher for the ideal matchup. And that pitcher comes armed with his best stuff.

"You're almost always going to have to hit the pitcher's best pitch," Weiss said. "The game's on the line; you're not going to get a fastball down the middle … and that's why it's tough to consistently perform in those situations."

After a July slump, August has been the best month of Arenado's young career, as he was hitting .323 with 10 hits over nine games.

Sick Cuddyer misses second straight game

DENVER -- Michael Cuddyer missed his second straight game because of illness Monday, when he was scheduled to be awarded the Major League Baseball Players Alumni Association Heart and Hustle Award for the Rockies.

Though manager Walt Weiss said Cuddyer could come to Coors Field during the game if he started to improve, the club told him to stay home to rest. It appears to be the same sickness that struck the Cuddyer household at the beginning of August, when he flew back to Denver to care for his family and missed two games.

Already without slugger Carlos Gonzalez, who is battling a sprained middle finger in his right hand, the Rockies opened their series against the Padres without two of their most important bats. Cuddyer leads the team with a .328 average and ranks second to Gonzalez with 66 RBIs.

First batter the toughest for Brothers

DENVER -- Rex Brothers has made things especially difficult for himself recently.

Brothers, who has assumed the closer role for the Rockies with Rafael Betancourt on the disabled list, has struggled to get the first batter out, often putting a runner on base before he turns into his usually dominant self.

In the 3-2 win over Pittsburgh on Sunday night, Brothers served up a leadoff single to Neil Walker, and then a double to Tony Sanchez, leaving runners at second and third with one out. Though Brothers escaped with the save, opponents are hitting .435 with five doubles off Brothers on the first pitch, the first hitter batting .283 with two homers and three doubles.

But Rockies manager Walt Weiss offered an explanation for Brothers' issues early in the ninth.

"The few innings that he's had where some guys got some hits off him, I think it's been a case where batters don't want to go deep into counts with him," Weiss said. "And so he's given up some hits on first-pitch fastballs where guys have ambushed him. They don't want to hang around for that slider. He's trying to get strike one, and they barrel it up. I think that's what's happened more than anything else."

Brothers, who owns a 1.49 ERA, has weathered the storms he has created, converting nine straight saves despite allowing three runs over his last eight appearances.

Range of factors in Tulo's current skid

DENVER -- Rockies shortstop Troy Tulowitzki insists nothing hurts but his numbers. Tulowitzki was leading the National League in batting with a .347 average and had a 1.048 on-base-plus-slugging percentage when he broke a rib on his right side June 13.

Since returning July 11, Tulowitzki hit .202 and has 24 strikeouts against 12 walks in 95 plate appearances entering Monday night's game against the Padres at Coors Field. During a 1-9 road trip that was the worst in franchise history, Tulowitzki hit .103 with eight strikeouts. While the Rockies swept the NL Central-leading Pirates in a three-game weekend series, Tulowitzki went 1-for-8 -- though he did draw four walks.

Any slump raises questions about the health of Tulowitzki's rib cage. He has avoided diving for balls to protect himself, but he said the rib cage is no factor in his skid.

"I'm not hurting at all," Tulowitzki said. "I feel good. It's just one of those stretches you go through. That's a big part of this game. You're going to go through tough stretches where you grind out at-bats until you get back to that comfort zone. You know they're going to come. It's just a matter of when they come. Just try to weather it."

Many factors converged to help create the slump. The Rockies played four games at Atlanta's Turner Field, where Tulowitzki is a .203 career hitter. He had two games against the Pirates' A.J. Burnett, against whom he is 1-for-11. The Mets' Matt Harvey dominated Tulowitzki and the Rockies the way he has done against almost everyone on every team.

Tulowitzki has a history of streakiness, with the positive in that being that he can turn sizzling hot without warning. When it happens, pitching to him is difficult, because he crushes outside pitches yet has enough power to cover the inside part of the plate and still hit the ball a long way.

"I don't know if it's just one key," he said. "Just overall the at-bats get a little bit better as far as working counts and starting to feel comfortable in the box. The biggest thing is getting in there and being in your comfort zone, instead of, 'Is this right? Is this right?' Comfort is probably the biggest thing."

Manager Walt Weiss expects Tulowitzki to find his comfort.

"I'm not worried about 'Tulo,'" Weiss said. "He's a great hitter, and that's never going to change. Even great hitters don't get two hits every night. So I have no concern about him; I think he's going to be productive in this game until the day he leaves it."

Betancourt throws successful sim game

DENVER-- Closer Rafael Betancourt threw a simulated game at Coors Field on Monday, another step forward as he recovers from an emergency appendectomy.

Betancourt had his appendix removed June 20 and has been on the 15-day disabled list since. But Rockies manager Walt Weiss said Betancourt was on track to make a rehab appearance with Triple-A Colorado Springs on Thursday.

"I think he threw close to 40 pitches, and it went well," Weiss said. "We'll see how he feels tomorrow, but the plan is for him to go out and pitch on Thursday. Then we'll go from there."

Lefty Rex Brothers has taken over closer duties in Betancourt's absence, converting nine straight opportunities.

Betancourt also reeled off four consecutive saves before being sidelined by injury and has converted 15 of 16 opportunities this year.

Ian McCue is an associate reporter for MLB.com. Thomas Harding is a reporter for MLB.com. Read his blog, Hardball in the Rockies, and follow him on Twitter @harding_at_mlb. This story was not subject to the approval of Major League Baseball or its clubs.