With Opening Day (March 28) of the 2019 Major League Baseball season just around the corner, it's crunch time for the various position battles going on around spring training.

We're here with updates for the apparent winners and losers of 10 especially important competitions, which involve compelling races for precious roster spots on contenders. We'll look at how they're being influenced by performances in exhibition games and other relevant factors.

The current "winners" of each competition aren't necessarily guaranteed to break camp with jobs in hand. Also, be warned that there are a couple of races that don't truly have "losers" as of yet.

We'll start with a catching competition and move on to three each of infield, outfield and starting rotation battles.

Boston Red Sox: Catcher

The Candidates: Christian Vazquez, Blake Swihart, Sandy Leon

The Boston Red Sox carried three catchers throughout 2018, yet only two will survive their spring training crucible for 2019.

"Last year, we had three, and we felt comfortable with it. This year is a different year. Most likely it's going to be two, and we're going to feel comfortable with it," manager Alex Cora said, per Alex Speier of the Boston Globe.

Of the three contenders—each of whom is out of minor league options—Blake Swihart is making the strongest offensive impression with an .865 OPS in Grapefruit League action. The 26-year-old's other big selling point is his ability to play in the infield and outfield.

Christian Vazquez and Sandy Leon, meanwhile, are excellent defensive catchers who usually don't offer much offense. So it goes this spring. Leon's OPS is an ugly .701. Vazquez's is an even uglier .333.

However, it was only last year that the Red Sox committed to Vazquez, 28, with a three-year contract extension. If they were looking to move on from him now, they probably wouldn't have had him catch staff ace Chris Sale in his spring debut Saturday. That's normally Leon's job.

Winners: Blake Swihart, Christian Vazquez

Loser: Sandy Leon

Colorado Rockies: Second Base and First Base

The Candidates: Mark Reynolds, Ryan McMahon, Garrett Hampson, Pat Valaika

Daniel Murphy is set to be the Colorado Rockies' everyday first baseman, but the club has a starting second base gig and two reserve infield spots up for grabs.

Hypothetically, the right-handed-hitting Mark Reynolds could platoon with the left-handed-hitting Murphy. However, he isn't boosting his case with a .675 OPS and 11 strikeouts in 32 at-bats this spring.

In the meantime, Ryan McMahon (1.241 OPS), Garrett Hampson (.996 OPS) and Pat Valaika (.970 OPS) are hitting the proverbial cover off the ball. They also offer more defensive versatility than Reynolds, who's really only playable at first base.

"Ultimately, the positive is that guys are playing hard, they are battling and they are showing what they can do," Rockies manager Bud Black said, per Patrick Saunders of the Denver Post. "Because of this, it's reassurance that we have depth, which is what you want."

The situation would be complicated if Reynolds were with the Rockies on a major league deal. But since he's on a minor league deal, the club isn't obligated to give the 35-year-old a roster spot.

Winners: Ryan McMahon, Garrett Hampson, Pat Valaika

Loser: Mark Reynolds

New York Mets: First Base

The Candidates: Pete Alonso, Dom Smith

Though J.D. Davis is technically in the mix to open 2019 at first base for the New York Mets, injuries to Todd Frazier and Jed Lowrie create a more immediate need for him at third base.

In actuality, the first base race is strictly between Pete Alonso and Dom Smith. And unlike the one on the other side of town, there isn't room for both of them.

Alonso, who rates as the Mets' second-best prospect, has a 1.058 OPS and four home runs through 16 spring games. This is coming on the heels of a 2018 season in which he racked up a .975 OPS and 36 homers at Double-A and Triple-A.

Smith, however, is keeping pace with a .906 OPS through 15 games. According to MLB.com's Anthony DiComo, the Mets are also "far more confident" in Smith's defensive abilities than they are in Alonso's. 

That would seem to be an excuse for the Mets to send Alonso down for the start of the season, yet general manager Brodie Van Wagenen has insisted he only cares about bringing "the best 25 guys" north. In other words, Alonso isn't necessarily doomed to fall prey to a game of service-time manipulation.

So at least for now, this is a truly neck-and-neck race.

Winners: Pete Alonso, Dom Smith

Pittsburgh Pirates: Shortstop

The Candidates: Kevin Newman, Erik Gonzalez

It wasn't that long ago that 22-year-old prospect Cole Tucker was making a run at the Pittsburgh Pirates' shortstop job. He was raking with a 1.339 OPS through 12 Grapefruit League games.

Nevertheless, the Pirates reassigned Tucker to minor league camp March 12. In so doing, they effectively made their shortstop competition a two-horse race between Kevin Newman and Erik Gonzalez.

Newman entered Pirates camp as the team's No. 9 prospect, and he's come alive at the plate after a slow start. The 25-year-old is up to a solid .739 OPS through 11 games, including a 3-for-4 performance last Thursday that included a homer and a double.

"That just gives more concrete evidence that he might be hunting the good stuff," Pirates manager Clint Hurdle said of Newman, according to Bill Brink of the Pittsburgh Post-Gazette.

For his part, Gonzalez is struggling offensively with a .670 OPS. The fact he's out of options gives him a security blanket of sorts, but he'll likely need to show the Pirates something for that to make a difference.

Winner: Kevin Newman

Loser: Erik Gonzalez

St. Louis Cardinals: Outfield

The Candidates: Marcell Ozuna, Harrison Bader, Dexter Fowler, Jose Martinez, Tyler O'Neill

On paper, the St. Louis Cardinals are set to roll with Marcell Ozuna, Harrison Bader and Dexter Fowler from left to right in their outfield, with Jose Martinez in reserve.

But it's clear Tyler O'Neill wants in.

The 23-year-old is only hitting .182, yet he's getting by just fine with a .794 OPS and four homers through 16 Grapefruit League games. Though he's primarily a corner outfielder, the Cardinals are at least willing to try him in center field.

Meanwhile, the presumed favorites for St. Louis' outfield jobs aren't doing so hot. Ozuna, who's coming off shoulder surgery, has a .362 OPS. Fowler is only doing a tad better with a .459 OPS. Bader is at .475. Martinez has a .687 OPS, but it comes with zero homers.

The biggest hurdle between O'Neill and a roster spot might be Yairo Munoz. He can play both the infield and the outfield, and he's hitting .303 with a .727 OPS this spring.

But at least until their assumed regulars come back to life, the Cardinals have to consider choosing O'Neill's upside over Munoz's versatility.

Winner: Tyler O'Neill

Losers: Marcell Ozuna, Harrison Bader, Dexter Fowler, Jose Martinez

Cincinnati Reds: Center Field

The Candidates: Nick Senzel, Scott Schebler

The Cincinnati Reds have been without a true center fielder ever since they non-tendered Billy Hamilton last November. They're hoping that either Nick Senzel or Scott Schebler will earn the job.

Schebler, 28, would seem to have the inside track by way of his experience. His major league track record includes a .781 career OPS and a peak of 30 homers in 2017. Albeit in limited exposure, he's also played passable defense in center field.

Further, Schebler isn't hurting his cause with a 1.268 OPS through 11 spring games. He's showing an especially advanced approach with 10 walks to only two strikeouts.

But while Senzel, 23, only has a .690 OPS this spring, he still has an exciting appeal that Schebler can't replicate. He's MLB.com's No. 6 overall prospect, and his transition from the infield to the outfield has been a breeze.

"He's really done everything he can to show that he has the ability to play center field," manager David Bell said, per Bobby Nightengale of the Cincinnati Enquirer.

Like with the Alonso vs. Smith contest in New York, something has to give with the Senzel vs. Schebler race in the final days of spring training.

Winners: Nick Senzel, Scott Schebler

Cleveland Indians: Corner Outfield

The Candidates: Greg Allen, Jordan Luplow, Tyler Naquin, Jake Bauers, Trayce Thompson, Oscar Mercado

The Cleveland Indians have Leonys Martin penciled into center field, but on either side of him are two huge question marks.

The Indians seemed to answer one of them by signing three-time All-Star Carlos Gonzalez on Saturday, but it's only a minor league deal and there's no guarantee that he'll be game-ready by Opening Day.

Meanwhile, veterans Matt Joyce (informed he won't make it) and Brandon Barnes (reassigned) are officially out of the running. That would seem to leave six candidates for two spots. Here's how they're performing offensively this spring:

• Oscar Mercado: 1.165 OPS, 3 HR
• Greg Allen: 1.148 OPS, 1 HR
• Trayce Thompson: 1.131 OPS, 1 HR
• Jake Bauers: .760 OPS, 2 HR
• Tyler Naquin: .604 OPS, 1 HR
• Jordan Luplow: .513 OPS, 0 HR

The winners and losers presumably break down accordingly, save for one exception. Bauers is a first baseman-type who'll only be needed in left field if veteran slugger Hanley Ramirez makes the Indians as a designated hitter. With only a .616 OPS so far, he's not exactly forcing the team's hand.

Winners: Oscar Mercado, Greg Allen, Trayce Thompson, Jake Bauers

Losers: Tyler Naquin, Jordan Luplow

Houston Astros: Starting Rotation

The Candidates: Brad Peacock, Framber Valdez, Josh James, Forrest Whitley

Yes, Forrest Whitley is out of the running for the Houston Astros rotation after being reassigned to minor league camp March 12. But he's still worth mentioning because of the impression he made.

Whitley, who ranks as MLB.com's No. 7 prospect, appeared in four games for the Astros and struck out 15 while allowing only two earned runs in 12 innings. It's clear that the 21-year-old doesn't need much more seasoning before he's ready for The Show.

Fellow prospect Josh James is an exciting young pitcher in his own right, but a quad strain delayed his spring debut until Saturday. Because of that, he's much more likely to make Houston's Opening Day roster as a reliever than as a starter.

Thus this race is whittled down to Brad Peacock and Framber Valdez, and one of them has a clear edge. Peacock has a 1.50 ERA with 10 strikeouts and one walk in 12 innings. Valdez has a 4.05 ERA with five walks and seven strikeouts through 13.1 innings.

Winners: Brad Peacock, Forrest Whitley

Losers: Framber Valdez, Josh James

Oakland Athletics: Starting Rotation

The Candidates: Frankie Montas, Jesus Luzardo, Chris Bassitt, Aaron Brooks

Elsewhere in the American League West, the Oakland Athletics are out to fill not one, but two spots in their starting rotation.

Frankie Montas has one of them all but sewn up. If him being out of options wasn't a good enough excuse for the A's to give him a job, the hard-throwing righty's 0.69 ERA, 13 strikeouts and three walks through 13 spring innings should do the trick.

Not to be outdone, Jesus Luzardo has a 0.93 ERA and 15 punchouts in only 9.2 innings this spring. Thus has the lefty lived up to being MLB.com's No. 12 overall prospect, perhaps to a degree that will make the A's think twice about sending him to the minors for the start of 2019.

"I thought he was great, again," A's manager Bob Melvin said following Luzardo's March 10 start opposite the San Francisco Giants, per Jane Lee of MLB.com. "He got off to a little bit of a rough start as far as balls and strikes, but it doesn't seem to bother him. He's got really good feel for what he wants to do."

Despite his 5.40 ERA, Chris Bassitt has made a strong case with 12 strikeouts and one walk over 10 innings. He should have an edge on Aaron Brooks, who has a 6.00 ERA and four walks against nine strikeouts in nine innings.

Winners: Frankie Montas, Jesus Luzardo, Chris Bassitt

Loser: Aaron Brooks

Milwaukee Brewers: Starting Rotation

The Candidates: Brandon Woodruff, Jimmy Nelson, Corbin Burnes, Freddy Peralta, Josh Tomlin

The Milwaukee Brewers also entered spring training with two open spots in their rotation. One of them now seems squarely in the hands of Brandon Woodruff.

The 26-year-old entered camp as a presumed favorite for a role, and he's cemented his status with a 0.00 ERA and 12 strikeouts in three Cactus League starts. He's walked four but only one in his last two outings.

As for the other spot, there's good news and bad news regarding Jimmy Nelson. The bad is that a minor setback in his return from shoulder surgery nixed his readiness for Opening Day. The good is that he's looking strong when he does pitch. He has seven strikeouts and no walks in four innings.

Corbin Burnes should be the top candidate to fill in for Nelson, but he's surrendered 19 hits and put up a 5.93 ERA over 13.2 spring innings. Josh Tomlin has been better, yet only to the tune of a 4.80 ERA and nine strikeouts over 15 innings.

Freddy Peralta, meanwhile, hasn't pitched as poorly as his 6.14 ERA would indicate. He's struck out 12 and allowed only four hits and three walks in 7.1 innings.

Winners: Brandon Woodruff, Jimmy Nelson, Freddy Peralta

Losers: Corbin Burnes, Josh Tomlin

Spring stats courtesy of MLB.com. Other stats courtesy of Baseball Reference and FanGraphs.