Spring training is upon us, which means the questions are only beginning.
Questions that must resolve in March. Questions that will linger into the regular season. Questions that will remain mysteries, perhaps, until October is over.
Well, one step at a time.
Here, broken down by divisions, is the biggest question that each team must address before Opening Day.

Red Sox: Who will be the catcher?
Sandy Leon was a revelation for much of 2016 before batting .213 with a .539 OPS in September/October. Once upon a time, both Christian Vazquez and Blake Swihart were considered the Red Sox’s potential catchers of the future. Maybe the time for one of them finally is arriving – though Swihart, as the only one of the three that can be optioned to Triple A, faces an uphill fight.

Blue Jays: Are further moves necessary?
The Jays’ off-season signings again were economically prudent, but Jose Bautista is 36, Kendrys Morales and J.P. Howell 33, Joe Smith 32. Meanwhile, first baseman Justin Smoak occupies a spot that could go to a better bat (Pedro Alvarez?) and the bullpen could fall under immediate scrutiny if Howell and/or Smith do not throw well in the spring.

Orioles: Where have you gone, Welington Castillo?
Orioles officials cannot be happy that Castillo, who was signed as a free agent to replace catcher Matt Wieters, will play for the Dominican Republic in the World Baseball Classic. Castillo is more an offensive asset than a defensive one, and the time he is away will be time that he could have spent acclimating to his new pitching staff.

Yankees: Do they need immediate rotation help?
We will not learn in the spring whether Greg Bird will hold down first base and Aaron Judge right field long-term. The bigger question, for the moment, is the state of the rotation, which is full of risk at the top (Masahiro Tanaka, Michael Pineda, CC Sabathia) and uncertainty at the bottom (Luis Severino, Luis Cessa, Bryan Mitchell, Chad Green, Adam Warren).

Rays: Can they stay healthy?
This question, of course, applies to every team, but the low-revenue Rays are in a more precarious position than most. A series of injuries, most notably to center fielder Kevin Kiermaier, helped wreck them last season. Shortstop Matt Duffy, right fielder Steven Souza and first baseman Logan Morrison – all coming off surgeries – need to bounce back strong.

Indians: Can they expect the same Corey Kluber?
While the team’s biggest question is whether left fielder Michael Brantley can return from shoulder trouble, let’s not forget how hard the Indians pushed Kluber last October – he threw 34 1/3 innings in the postseason, bringing his season total to 249 1/3, and made three starts on three days rest. The Indians are certain to proceed with caution this spring.

Tigers: Who will play center field?
The Tigers have far deeper issues; even if they contend, that will only prolong their inevitable roster teardown. As it stands, outfielder Cameron Maybin was the only significant player the Tigers traded, creating a competition in center between Tyler Collins, JaCoby Jones and the newly acquired Mikie Mahtook.

Royals: How will they recover from tragedy?
The front office signed free-agent right-hander Jason Hammel to replace Yordano Ventura, who died last month in a car accident at age 25, and reached agreement with lefty Travis Wood, another potential starter. The bigger question, perhaps, is how the players will respond to Ventura’s absence from their day-to-day baseball lives. The Royals already were dealing with different uncertainty — the potential free agencies of Eric Hosmer, Mike Moustakas, Alcides Escobar and Lorenzo Cain.

Twins: Can Miguel Sano handle third base?
He reported overweight last spring and took poorly to right field. But third base finally opened full-time after the Twins parted with Trevor Plouffe, and now the burden is on Sano to establish himself as more than a DH. The ascensions of Sano and Byron Buxton into stars are still the Twins’ best hope, provided that at some point they improve their starting pitching.

White Sox: Who will be the next player traded?
The White Sox will continue weighing offers for left-hander Jose Quintana and others, but understand that Quintana and closer David Robertson might bring more at the non-waiver deadline if they perform well in the first half. Three potential agents – Todd Frazier, Brett Lawrie and Melky Cabrera – remain highly available.

Astros: Will they get a starting pitcher?
Spring-training blockbusters are rare, and the Astros already have spent the entire off-season trying to land a top-of-the-rotation starter. Quintana, the Athletics’ Sonny Gray and Rays’ Jake Odorizzi were among their top targets, and each still can be had if the Astros meet a certain price. An injury to one of the ‘Stros’ projected starters would only increase the team’s urgency.

Rangers: Does Josh Hamilton still have it?
If so, the Rangers have their DH. Hamilton, who turns 36 in May, should be motivated – his original five-year, $125 million free-agent contract with the Angels expires after this season. The question is whether he is healthy after missing all of last season while recovering from knee surgery. The Rangers’ other options at DH include James Loney, Will Middlebrooks and Travis Snider, all of whom are on minor-league contracts.

Mariners: How quickly they can gel?
Spring training actually will be a meaningful bonding experience for the M’s – their 25-man Opening Day roster figures to include at least 10 players who were not with the club at the start of last season. Chemistry can be overrated, but teams that undergo dramatic transformations sometimes need time to find their rhythm. GM Jerry Dipoto is at 13 off-season trades and counting.

Angels: How healthy are the starters?
GM Billy Eppler added a number of interesting parts on the position-player side, but it all will mean little if Garrett Richards and Co. do not return to form. Richards underwent stem-cell treatment to avoid Tommy John surgery, and Matt Shoemaker missed the final month due to a skull fracture after getting hit by a comebacker. Tyler Skaggs should be more consistent in his first full year removed from Tommy John.

Athletics: Will Sonny Gray be on the Opening Day roster?
The Athletics could not get their desired value for Gray after he posted a 5.69 ERA in his injury-marred 2016 season. However, a prospective suitor might jump if Gray shows early signs of a revival pitching for Team USA in the World Baseball Classic. The A’s are building an intriguing young nucleus; trading Gray would allow them to collect even more young parts.

Nationals: Is the bullpen good enough?
The Nats’ talks for White Sox closer David Robertson seemingly are at an impasse, so expect the team’s pursuit of bullpen help to continue all spring. The party line is that the Nats are happy with their internal options – Blake Treinen, Koda Glover, Shawn Kelley, etc. But after striking out on free agents Mark Melancon and Kenley Jansen, what else can they say?

Mets: What can David Wright offer?
The Mets face bigger long-term questions – the health of their starting rotation, the future of outfielder Michael Conforto – but Wright is an immediate concern. He recently turned 34 and has appeared in only 75 games the past two seasons due to serious back and neck issues. Jose Reyes will go from a super-utility man to the regular third baseman if Wright is again unable to perform.

Marlins: Can Edinson Volquez recapture his 2014-15 magic?
Spring training will not provide a full answer, but for Volquez it could be the first step toward a revival. The Marlins, following the death of Jose Fernandez last September, signed Volquez, traded for Dan Straily and added Jeff Locke on a minor-league deal. None is close to Fernandez’s equal, but Volquez at his best is a quality innings-eater with leadership ability.

Braves: Which youngsters will shine brightest?
The Braves hold eight of the game’s top 78 prospects, according to Baseball America. Dansby Swanson, No. 3 on the list, will be the team’s starting shortstop. Second baseman Ozzie Albies (No. 11) and left-hander Sean Newcomb (No. 78) are getting closer to the majors. It will be fascinating to see which of the kids generates the most buzz.

Phillies: Will J.P. Crawford rebound?
Crawford, the Phillies’ shortstop of the future, is coming off a disappointing, injury-marred season; he batted only .244 with a .647 OPS after moving to Triple A. On the other hand, he just turned 22, and Baseball America still rates him as the 12th prospect in the game, down from No. 6 a year ago. A good camp by Crawford, and Freddy Galvis will be in trouble; his .274 on-base percentage last season was the lowest in the majors.

Cubs: How well did the starting pitchers recover?
As one Cubs official put it, referring to the team’s World Series run, “It would be unrealistic not to expect some kind of pitching hangover.” The extent of that hangover might not be evident in the spring, but the Cubs managed their starters carefully all last season. The final innings totals, including postseason: Jon Lester 238 1/3; Jake Arrieta 219 2/3; Kyle Hendricks 215 1/3; John Lackey 201 2/3.

Cardinals: Did they actually fix the defense?
Dexter Fowler in center, Kolten Wong at second, Randal Grichuk in left, Aledmys Diaz in his second full season at short – it sure sounds better. And, though spring-training games matter little, manager Mike Matheny is sure to emphasize crisper defense from the start of Grapefruit League play. The Cardinals need to set a tone early and carry their focus into the season.

Pirates: What’s next for Andrew McCutchen?
The answer at the moment is, “right field,” McCutchen’s new position after 10,317 1/3 career innings in center. A trade, though, is inevitable, and a big spring by top outfield prospect Austin Meadows could help force the issue sooner than later. McCutchen will be hellbent on a comeback season either way.

Brewers: How creative is creative?
The Brewers will open camp with at least seven potential starters for five spots, and manager Craig Counsell has said he will “consider” different ways of deploying his pitching. What that means is not yet clear, but a rebuilding team is the perfect laboratory to experiment with different usage patterns.

Reds: Could Zack Cozart go, too?
A spring-training trade of Cozart might only be possible if another team’s shortstop suffers an injury, but the Reds finally moved second baseman Brandon Phillips on Sunday, and Cozart also is a potential free agent. The team wants to rebuild with Dilson Herrera and Jose Peraza up the middle. The more playing time those two get in 2017, the better off the Reds will be long-term.

Dodgers: How many trades will they make?
Something has to give, assuming good health -- the Dodgers will open the spring with surpluses of starting pitchers, outfielders and reserves. A roster crunch appears inevitable; difficult decisions await. Right-hander Brandon McCarthy and left-hander Scott Kazmir were trade candidates all off-season. And if outfielder Yasiel Puig remains with the club, it might not be in an everyday role.

Giants: Who will play left field?
Look ma, an actual head-to-head competition! GM Bobby Evans has said his preference is for Jarrett Parker or Mac Williamson to win the job outright, and Parker is out of options. Neither is exactly a prospect – Parker is 28, Williamson 26 – and it could be that the Giants look for modestly priced upgrades throughout the spring.

Rockies: Are the young starting pitchers ready?
The youth of the Rockies’ rotation – combined with the relative inexperience of their catchers – is striking. None of the Rockies’ projected starters is older than 27. None has made more than 90 career starts. The two catchers, Tony Wolters and Tom Murphy, have appeared in 103 major-league games combined.

Diamondbacks: Might they still trade a starter?
If everyone stays healthy, why not? Zack Greinke, Robbie Ray and Taijuan Walker will occupy the top three spots. Shelby Miller, Patrick Corbin and Archie Bradley are vying for the final two, with decent alternatives behind them. The D-Backs remain in good position to exploit their relative depth.

Padres: How bad will the rotation be?
Spring training is not too early to ask this question; Fangraphs currently projects the Padres’ rotation to be the worst in the majors. That could change; the team continues to explore free-agent alternatives such as lefty Travis Wood and righty Jered Weaver. But for now, try picking an Opening Day starter from Jarred Cosart, Jhoulys Chacin, Clayton Richard, Trevor Cahill, Christian Friedrich and Luis Perdomo.