Puig, Machado, Samardzija among second-half's biggest X-factors

With the second half set to start, which players could make the biggest difference down the stretch? Albert Chen picks his five X-factors to watch.

We saw the Chosen One fulfill the prophecy and become the best player on the planet. We saw the earlier-than-expected arrival of two rising powers set for world domination (the Astros and Cubs). We saw the debuts of phenoms who will rule the game for the next decade (Kris Bryant, Joc Pederson, Carlos Correa), as well as the improbable resurrections of sluggers we were sure were cooked (Alex Rodriguez, Albert Pujols).

The first half of the season belonged to Bryce Harper’s home run trot, Josh Donaldson’s defensive stylings, Dallas Keuchel’s unstoppable beard, Johnny Cueto’s dreads, the precocious Cubs, the ornery Royals and the boring Cardinals. Now we are at the halfway point, trying to guess what will happen next. A Twilight Zone postseason field that includes the Astros, Cubs and Twins? A Triple Crown for Paul Goldschmidt? An MVP for Manny Machado? Who knows? With the season’s second act about to begin, here are five players who could be X-factors down the stretch.

• MORE MLB: Tom Verducci breaks down each team for second half

The forgotten phenom

It’s a debate we’ll be having years from now: Whether this breathtaking 2015 rookie class—headlined by the masher from Vegas (Bryant), the next great Dodger (Pederson), and the second coming of A-Rod (Correa)—is the best ever. They keep coming, too, as we’ve recently been treated to the smashing debuts of Mets starter Steven Matz (now sidelined with a lat injury) and the Twins' Miguel Sano. The latter is a prospect who’s been overshadowed by teammate and No. 1 prospect Byron Buxton, who is currently on the disabled list with a thumb injury. But while Sano arrived to less fanfare than Bryant and Correa, he may turn out to be the rookie who will make the biggest impact in the second half.

Cueto to Royals, Tigers out of playoffs and more bold AL predictions

​Sano’s legend has been growing since he signed with the Twins six years ago. In the biggest moment of his life—with an army of major league officials in attendance and a potential multi-million dollar contract at stake—a 15-year-old Sano stepped to the plate at the Twins' facility in the Dominican Republic and hit eight straight balls out of the park. The last one cleared a flag beyond the centerfield wall, went over some trees and a creek and landed on a parking lot. The Twins signed him days later.

Sano made his debut on July 2 and has recorded 14 hits in his first 11 games; through 45 plate appearances, he's hitting a red-hot .378/.489/.649 with two homers. “The [Twins'] offense has been a surprise,” a scout said. “The lineup has surprising depth, and Sano, he’s a perennial 30-home run threat [and] is exactly what they need, a power hitter in the middle of the order.”

Alex Gordon’s injury could be a game changer in the AL Central race. With the Royals’ best player—Gordon is the most patient hitter in a free-swinging lineup and the best leftfielder in the game—sidelined and with the Tigers' Miguel Cabreraout until at least mid-August, the AL Central suddenly feels like it’s up for grabs. The Twins are just 4 1/2 games back, and if Sano catches fire, don't be surprised if Minnesota is the AL team that shocks the world.

The enigma

The Dodgers may seem like a beautifully constructed, $230 million ocean liner cruising toward the October horizon. But don’t let the NL West standings—where the Dodgers are 51–39 and 4 1/2 games up on the Giants—fool you: Los Angeles is a flawed team, and complicated waters are ahead. Adrian Gonzalez (.194/.237/.611 since July 1) and Pederson (.132/.214/.211) are no longer fixtures in your daily fantasy lineups; Jimmy Rollins is somehow still the starting shortstop despite a meager 68 OPS+; and that rotation behind Clayton Kershaw and Zack Greinke is thinner than Clark Gable’s mustache.

Cubs in playoffs, Ozzie back in Miami and more bold NL predictions

​Yasiel Puig, though, can get things done, and we’re not just talking about making dinner plans during at-bats. He is still the most talented position player on that $230 million roster—over 2013 and '14, he was one of the 20 most valuable players in the game—but it was beginning to look like something of a lost season for him after he missed 39 games with a left hamstring strain, then was slowed with by a blister on his hand. But just before the break, Puig showed off the talent that can save a season, driving in four runs with a double and a homer in a win over the Phillies on July 9.

The Dodgers have built their lead in the division without much of a contribution from Puig in the first half, but let’s not forget how important he is to this team. As a middle-of-the-pack offensive team with real concerns in the rotation, Los Angeles needs his production. If Puig can rediscover his mojo, he can do a lot more than make dinner plans for the Dodgers—he can turn them into a true juggernaut.

The trade deadline difference maker

In his final start of the first half, Jeff Samardzija took on the best offense in baseball and delivered his first shutout of the season, allowing just four hits over nine innings and striking out five to beat the Blue Jays. It was his fifth quality start in his last six starts and his sixth straight outing in which he went at least seven innings, and for the second straight start, Samardzija took a no-hitter into the sixth. As trade rumors heat up, the 30-year-old righthander is catching fire.

Awards Watch: Your MVP, Cy Young and ROY leaders at All-Star break

No, Samardzija is not Cole Hamels, nor is he Cueto, but he is a top-of-the-rotation starter who will not cost a team a raft of elite prospects. His numbers on the surface might not suggest that he’d be a game-changing acquisition for a pitching-starved contender—he’s 6–4 with a 4.02 ERA and has allowed the second-most hits (130) of any pitcher in baseball. But his ERA is higher than it should be, as he’s pitched in front of a horrendous defense (only two teams, the Phillies and Yankees, have posted a worse Defensive Runs Saved figure than Chicago's -30), and he’s also been pitching in one of the most homer-friendly ballparks in baseball, U.S. Cellular Field.

At the start of July, the White Sox looked hopeless, and a trade deadline dismantling seemed inevitable. But they've won eight of 11 this month, and while they’re still languishing four games under .500 and 11 games behind the Royals in the AL Central, they’re also just 5 1/2 games out of a Wild Card spot. But even if the team isn't ready to punt on 2015—this is, after all, Year 1 in what was hailed as a three-year plan in the South Side in the aftermath of the flurry of deals this winter—it still makes sense for Chicago to take advantage of an extreme seller’s market and deal a pitcher who’s headed toward free agency after this season while holding onto pieces like Chris Sale, Jose Quintana, David Robertson and Adam Eaton.

The minor league masher

The Cubs are 47–40, good enough for the second Wild Card slot if the season ended today, and the team is a unit full of young, preposterously talented players whose swagger seems to grow by the day. Seven years removed from their last postseason appearance, you have to like the Cubs' chances of playing this postseason, and with Jake Arrieta and Jon Lester atop the rotation, the idea of a run deep into October isn’t insane. But Chicago, perhaps one or two pieces away from being a championship team, likely won’t be an aggressive buyer at the deadline, nor should it be—dealing away young talent for an ace rental would seem counter to its philosophy.

Power Rankings: Cardinals edge Pirates for top spot as first half ends

But down at the farm, the Cubs may have a difference maker. Kyle Schwarber, the team's 2014 first-round pick, has destroyed Triple A in his first taste, hitting .333/.403/.633 with three home runs in 67 plate appearances. He has mashed at every level as a pro—even at the major league level. Over a one-week stint in the majors in June, he had eight hits in 23 plate appearances, with a homer, a triple and six RBIs. He was optioned back to Iowa on June 21, but with Miguel Montero going on the disabled list with a left thumb injury, the Cubs have brought Schwarber back to the majors. Schwarber clearly can add some pop to a lineup that has struggled recently—Chicago is averaging just over three runs per game in July. And while he still needs more time to hone his catching, the Cubs always knew that Schwarber's bat would be ready before his glove.

Even if the Cubs don’t make a big trade in July, they could be making a significant addition with the callup of their 22-year-old prospect. He showed off his skill by winning Futures Game MVP honors in Team USA's rout of the World Team in Cincinnati. Chicago hopes he can make a similar impact in the NL Central this summer and fall.

The unlikely MVP candidate

Picking the 25-and-under All-Stars as wave of young talent makes impact

It was just a few years ago that Manny Machado was being mentioned with Mike Trout and Harper as one of the game’s great young players, and yet his sudden rise as a real MVP candidate this year seems like it’s come out of nowhere, mostly because he’s still just a 23-year-old who’s never made it through a full season. But now Machado is second only to Trout in Baseball Reference's WAR among AL position players, and he is on pace to become the Orioles’ first ever 30–30 player. He has had a star-making first half, culminating in a deserved All-Star Game selection, but given his age and the fact that he’s still figuring things out at third base (he played short until he arrived in the majors), it’s obvious Machado's best is yet to come, and that should be frightening to the rest of the baseball world.

The Orioles are once again defying the computer projections, and with another run at the AL East crown—in third place in the division but just four games behind New York—you could argue that they are the division’s most complete team, as the Yankees (who can’t seem to find consistent starting pitching), Blue Jays (who also have some serious rotation issues), and Rays (the second lowest scoring team in the league) have clear flaws. If Machado keeps this up—and, barring injury, there’s no reason why he won’t—then he could not only carry Baltimore to a second straight division title in a very winnable AL East, but he could also be right in the middle of the MVP discussion at season’s end. Who've you got for the next 10 years: Trout, Harper, or Machado? Ask again when this crazy season is over.