Pivotal second-half players: National League

Now that Major League Baseball's first-half sensations are back from the All-Star break, it is time to get serious and validate their individual status for the 2013 season. And if that pushes their team into the postseason, all the better.

In the National League last season, key second-half performances by catcher Buster Posey and third baseman Pablo Sandoval helped push the San Francisco Giants to a World Series. Posey was the NL MVP and Sandoval the World Series MVP.

This year, the second[half performances of Posey and Sandoval will once again be critical. But unless the entire team improves around them, the Giants will be hard pressed to leverage their feats even if Posey bats .500 and Sandoval becomes the best pound-for-pound hitter in baseball.

Several players obviously will be pivotal after the All-Star Game break, but perhaps like Posey and Sandoval -- not necessarily with the postseason as an attainable team goal.

Ryan Braun has a shot to help the Milwaukee Brewers if he stays on the field and away from injuries. There were concerns of a possible suspension related to the Biogenesis investigation, but union officials contend that even if there are penalties they probably won't be levied until next year.

Based on a survey by team correspondents with The Sports Xchange, here is a closer look at the National League's pivotal players in the second half:

Arizona Diamondbacks -- RHP Ian Kennedy.

Kennedy led the NL with 36 victories in 2011-12, but has only three at the break (and a 5.42 ERA). He has at various times been up in the zone with his pitches, and his secondary stuff seems to be there one start, not the next. It has been a disjointed season, including the 10-game suspension for hitting two batters on June 11. The D-backs need Kennedy to be an ace in the coming months.

Atlanta Braves -- OF B.J. Upton.

In B.J. Upton, Justin Upton and Jason Heyward, the Braves believed they had one of baseball's best outfields entering the season. With the exception of Justin's 12 homers in April, the first half was a dud. The most pressure is on B.J. to rebound in the second half, but the Braves need all three to step up. Of course, they first have to get healthy, with all three hurting and B.J. on the disabled list.

Chicago Cubs -- SS Starlin Castro.

Castro went through some brutal stretches, batting .167 in June before heating up in the two weeks heading up to the All-Star break. Castro was the first of the "core" players that team president Theo Epstein and GM Jed Hoyer locked up, giving him a seven-year, $60 million contract extension last year. Castro seems to have regained confidence at the plate, and his defense has improved markedly in recent weeks. A strong second half will reassure the Cubs and their fans that the poor start was just a blip.

Cincinnati Reds -- OF Ryan Ludwick.

Ludwick had surgery after injuring his left shoulder (throwing) on Opening Day. The rehab process is an extensive one. Ludwick didn't begin baseball activity until early July -- three months after the surgery. He likely will return in mid-August. The Reds can use his bat and his presence. The team is shy on veteran leadership among position players.

Colorado Rockies -- SS Troy Tulowitzki.

Tulowitzki plays Gold Glove-caliber defense at a premium position and hits cleanup. The Rockies know all too well what his prolonged absence from the lineup means. The Rockies went 9-16 during his latest DL stint. Because of his past injury history, including a groin injury last year that ended his season on May 30 and required surgery, Tulowitzki is now very diligent about a pregame stretching/exercise routine and smarter about when to conserve his effort on the field. When he's on the field, he's an MVP candidate. Tulowitzki has a slash line of .332/.400/.608 with 16 home runs and 52 RBI and has made only two errors.

Los Angeles Dodgers -- CF Matt Kemp.

Kemp narrowly lost the NL MVP to Brewers OF Ryan Braun two years ago. The Kemp the Dodgers have seen this year has been a mere shadow of that player, due mainly to his difficulties recovering from last October's shoulder surgery.

Miami Marlins -- RF Giancarlo Stanton.

Miami's lack of consistent offense led to a putrid first half. Stanton missed most of May with a hamstring strain and never really got comfortable. Miami has a chance to avoid a 100-loss season and maybe even a last-place finish, but it won't happen unless Stanton starts producing on a consistent basis. He went into the All-Star break batting .250 with 10 homers and 27 RBIs -- the worst full first-half of his career. He has a history of strong post-All-Star break performances, including 18 second-half homers last season.

Milwaukee Brewers -- LF Ryan Braun.

The future of the Brewers -- 2013 and beyond -- rests largely on the fate of Braun. He missed more than a month with a thumb injury that compromised his power before going on the DL. Whether he is able to move past that issue in the second half is key for the Brewers. Beyond that, he has MLB's investigation into the Biogenesis clinic hanging over his head, with a possibly franchise-devastating suspension looming.

N.Y. Mets -- 1B Ike Davis.

Davis turned around his miserable first half by bashing 20 home runs after the break in 2012, rediscovering the power stroke that had gone missing for the better part of three months. Davis already looks like a different player this year since returning from Triple-A Las Vegas, but to remain a pivotal building block for the future, he will need to go on another tear.

Philadelphia Phillies -- LHP Cole Hamels.

Playoffs? Not without Hamels pitching like an ace. Bothered by a lack of run support in some games and ineffectiveness in others, Hamels had been lost on the mound until June. During his final three starts leading up to the break, he appeared to regain his 2012 form.

Pittsburgh Pirates -- 1B Garrett Jones.

Jones is hitting just .253 with eight home runs and 35 RBIs in 86 games, not what the Pirates were expecting after signing him to a one-year, $4.5 million contract as a second-time arbitration-eligible player last winter. Jones isn't likely to duplicate his .286 batting average and 27 homers of a year ago, but could still give the offense a sizeable lift.

St. Louis Cardinals -- LF Matt Holliday.

Holliday suffered a right hamstring injury and could be doubtful for the start of the second half, and his batting average is some 45 points under his career average. The Cardinals have some coverage for an injured Holliday with Matt Adams able to play first and Allen Craig in the outfield. But not having a healthy -- or productive -- Holliday will be hard to overcome.

San Diego Padres -- 3B Chase Headley.

Since his breakout second half in 2012, Headley has been mired in a prolonged slump spanning 60 games. In his last half of 2012, he hit .308 with 23 homers and 73 RBIs in 75 games, leading the National League in homers and RBIs after the break and led the league in RBIs at the end of the season with 115. In the 60-game stretch before the All-Star break, Headley hit .184 (45-for-244) with three home runs and 19 RBIs and is hitting .229 for the season.

San Francisco Giants -- 3B Pablo Sandoval.

Weight always is an issue with Sandoval, who has amazing athleticism and agility despite his body type, and for the most part the Giants must accept the third baseman as is. If that means a second-half surge, all the better. With Buster Posey and Hunter Pence, the Giants have a potentially lethal 3-4-5 combination, and much of it rests with the free-swinging Sandoval.

Washington Nationals -- OF Bryce Harper.

RHP Stephen Strasburg is always going to be a pivotal player on this roster. But one of the main reasons the Nationals could never seem to get into a groove offensively in the first three months of the season was not having a healthy Harper every day. Harper has hit .264 with 13 homers and 29 RBIs in just 57 first-half games. The Nationals need him to play every day and hit well to have a shot in the second half. As Major League Baseball breaks for the All-Star Game and the first-half sensations stop for a trip of the cap, their work is only half finished. The ability to sustain their level of play will go a long way in determining how teams finish the season.