DUNEDIN, Fla. — In the baseball world, spring has sprung.

Or close to it, anyway.

A total of 59 Toronto Blue Jays hopefuls have their ticket booked to the big-league side of spring training, and the Bobby Mattick Training Center will be the site of the annual hustle and bustle once again when pitchers and catchers start filing into the complex Tuesday.

No matter who ends up on the 25-man opening day roster 45 sleeps from now, it’s a team littered with question marks and unknowns.

Because many of them are the same questions that led to a disappointing 76-win season in 2017, you’re already privy to the problems, but some of the circumstances have changed this winter.

Here are 10 players to keep a close eye on this spring:

1. SP Aaron Sanchez

Sanchez has been talked about ad nauseam over the past calendar year. 

In fact, it was around this time last year that his blister issues appeared on the radar as a potentially serious problem — and they were.

Simply put, Sanchez is the key to the Jays’ hopes this season.

Sanchez has been throwing in Dunedin for a few weeks without any reported problems, but the tricky part about blisters is they’re unpredictable and tend to not show up until the stress, weather, workload or bad baseballs find a way to aggravate them.

The Jays will be monitoring Sanchez’s troublesome middle finger on an inning-by-inning basis this season, and the process of getting the 25-year-old back to top-of-the-rotation form starts this week.

2. SP Joe Biagini

Sent home for the winter with strict instructions to maintain his body and work on smoothing out his delivery from the windup, Biagini is currently pencilled in as the fifth starter.

But the Jays have been monitoring the free-agent starter market, trolling for a reasonably priced arm that would likely bump Biagini back to the bullpen where he’s excelled.

Until then, however, the Jays will keep the 27-year-old righty stretched out and hope he shows a winter of hard work has paid off.

3. SS Troy Tulowitzki

If healthy, Tulowitzki is going to be the opening day shortstop.

There are $58-million guaranteed reasons why.

But one of the talking points this winter coming from the Blue Jays’ front office surrounded last year’s slow start and what they could possibly do differently in the spring to avoid another awful April, a theme surrounding this franchise for a number of years.

The Jays aren’t going to rush Tulowitzki back from ligament damage to his right ankle, but if there’s a veteran who could use a solid sampling of Grapefruit League at-bats to iron out some of the kinks, this is the guy.

Spring performances always need to be taken with the entire salt shaker, but no one would be mad at seeing Tulowitzki swinging it well.

4. 2B/SS/3B Aledmys Diaz

From 2016 National League all-star to afterthought.

That’s where Diaz found himself suddenly in the St. Louis Cardinals’ organization, so a fresh start was asked for and granted in December.

It cost the Jays outfield prospect J.B. Woodman, a second-round pick in 2016, but Diaz’s upside is significant if he’s anywhere close to what he was two seasons ago.

Even if you split the difference, it’s probably a valuable depth piece for manager John Gibbons. But keep in mind Diaz has an option left and could start the season in Triple-A depending how things go with the health of Tulowitzki and Devon Travis.

Keep an eye on where Diaz plays defensively, as they try to work him into the super-utility role that’s become so important around baseball.

5. 2B/SS Lourdes Gurriel Jr.

Speaking of that super-utility role, Gurriel is a $22-million investment the Jays believe has the type of skillset to do just that.

The numbers were extremely muted in his first go-round in the minors, but the front office is giving the 24-year-old the benefit of the doubt and time to shake off the rust that came along with his defection from Cuba.

His older brother, Yuli, was much more productive in his second season in North America with the Houston Astros, and the Jays are hoping Lourdes adjusts in the same way.

While he’s been strictly a middle infielder thus far, expect to see Gurriel’s versatility continue to be a focal point in his development and outfield time could be in his future.

6. RP John Axford

As fun as it is to follow him because he’s a Canadian with an affinity for facial hair, the Jays believe the Port Dover, Ont., product can also serve as valuable bullpen depth.

There’s no getting around the fact Axford was simply awful last season, posting a 6.43 ERA to earn his release from the Oakland A’s last August.

But you could also point to Axford’s career 3.71 ERA and wonder if he’s this year’s Joe Smith, an under-the-radar veteran who’s capable of a bounce back.

Unfortunately, you have to go all the way back to 2011 to find the last time Axford had an ERA under 3.95.

In addition to the 35-year-old Axford, major-league veterans Craig Breslow, Jake Petricka, Al Alburquerque, Rhiner Cruz, and 2010 Blue Jays’ first-rounder Deck McGuire, who took a circuitous route to his MLB debut last year with Cincinnati, are all hoping to somehow earn a roster spot via minor-league pacts.

Canadians Andrew Case (New Brunswick) and Jordan Romero (Markham) will also be in big-league camp. 

7. C Reese McGuire

At this point, fellow prospect Danny Jansen is seen as the well-rounded catcher of the future.

That likely means he’s ticketed for a full-time role with Triple-A Buffalo because you can’t expect the 22-year-old to develop on a major-league bench.

That leaves Luke Maile and McGuire as the only other catchers on the roster behind veteran Russell Martin, who turns 35 on Thursday.

When you combine the fact McGuire doesn’t have an at-bat above Double-A with the realization he missed more than half the season last year with a knee injury, it would definitely be considered a surprise to see the 22-year-old make the opening day roster.

But he’s at least an equal, if not superior, to Maile defensively, leaving the window slightly ajar this spring if McGuire can do enough (anything?) with the bat.

Jansen being added to the 40-man roster this winter was a no-brainer, but McGuire was added, as well, suggesting the Jays see a player who could be on the verge of contributing.

8. OF Teoscar Hernandez

He was the projected starting right fielder until GM Ross Atkins swung a deal for a player with a similar power profile in Randal Grichuk.

Now, barring injury, Hernandez seems in line for another stint in Triple-A when you’re on the outside looking in at a left-field mix that includes lefty-swinging Curtis Granderson and right-handed Steve Pearce, as well as lefty Ezequiel Carrera.

However, there are ways you could envision Pearce and the $6.25-million owing in the final year of his contract going bye-bye or getting buried if the Jays believe the right-handed hitting Hernandez is ready.

If the 25-year-old continues the power binge he started last September (.602 slugging percentage), Hernandez could force his way onto the roster.

9. SP Taylor Guerrieri

The 24th overall pick in the 2011 draft, arm injuries have derailed Guerrieri’s ascent.

Last year, the 25-year-old right-hander was limited to just two Triple-A starts, before the Jays claimed him off waivers from the Tampa Bay Rays in November.

It’s the type of transaction that’s usually either ignored of scoffed at, but the pedigree and level of success when he was actually on the mound in the minors (2.51 ERA in six MiLB seasons) provide hope for the reclamation project.

10. RP Tim Mayza

Mayza was a spring darling last year, consistently pumping mid-90s gas from the left side.

While his results at Double-A and Triple-A continued to be encouraging last season, Mayza was lit up to the tune of a 6.88 ERA in the majors, allowing three homers in just 17 innings.

The underlying numbers were quite a bit more impressive.

The 2013 12th-round pick struck out a whopping 27 batters in those 17 frames, proving his stuff works when he’s not grooving it.

It may not be in April, but expect Mayza to play a significant role at some point this season. ​