DUNEDIN, Fla. — With the Toronto Blue Jays now into the latter half of spring training, the club’s most interesting camp competition is only getting more difficult to call. Right-hander Luis Santos was the latest reliever to make a strong push in the race for Toronto’s final bullpen spots Sunday, as he tossed two strong innings against the Pittsburgh Pirates.

The 27-year-old is very much in the mix for the opening day roster, along with fellow veterans John Axford, Tyler Clippard and Al Alburquerque, who have all been throwing well this spring. The Blue Jays have another couple weeks to mull things over. And that’s a good thing — because they’re being presented with some very tough decisions.

“Extremely,” said Blue Jays pitching coach Pete Walker. “I’m sure these will all be decisions that go right to the end. They’re all doing a great job right now. And we’re getting a really good look at them all.”

Santos has been quietly exceptional this spring, allowing only two baserunners — on a walk and a hit by pitch — over six innings. He’s struck out six, while getting 44 per cent of his outs on the ground, mixing and matching with his 93-m.p.h. fastball (which touched 95 a couple times Sunday), 86-m.p.h. change-up, and 82-m.p.h. curveball.

“We love him. He’s doing everything we’ve asked him to do and he throws strikes,” Walker said. “He has very effective secondary stuff. And the power’s a little bit more than I anticipated, to be honest with you. I think it’s a great mix. He really keeps hitters off balance.”

Part of that is thanks to Santos varying his times to the plate and utilizing different arm slots. He’s also showing plenty of confidence and poise on the mound, working purposefully and efficiently.

Blue Jays fans got a brief look at Santos last September when he was called up after rosters expanded. He pitched to a 2.70 ERA over 16.2 innings, striking out 16 and showing an ability to pitch multiple innings when needed, logging two or more in four of his 10 outings.

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The Blue Jays plan to use Santos’s next few outings to continue assessing him over multiple innings, and test his ability to bounce back from longer outings. Toronto’s strong preference is to carry a multi-inning reliever in the bullpen to start the season.

“We need that. You can’t just have seven one-inning guys down there,” Walker says. “You certainly need a little versatility, and guys who can go more than an inning, two, maybe even three.”

Axford has been just as impressive. He’s featured a 96-m.p.h. fastball all spring, allowing only a hit and two walks while striking out five over four innings pitched. And one of the walks was thanks to some extremely questionable umpiring. If not for that, his camp would look even better.

Axford’s also impressed the Blue Jays with his ability to induce groundballs. Thanks to a sinker he’s been developing for a few years, Axford’s gotten half his outs on the ground this spring.

“There’s a couple of pitches that we feel could be really effective for him,” Walker said earlier this week. “And he’s utilizing them this spring. The sink on his fastball is better than I anticipated. And his slider — small slider, cutter, call it what you will — it could be a really effective pitch, as well.”

Clippard is another strong candidate, although he’ll need to show his new club more than just the one scoreless inning he’s thrown thus far. Clippard was signed to a minor-league deal Wednesday, and Blue Jays manager John Gibbons has been preaching the value of his experience since. Clippard would also provide Gibbons with a second option against left-handed hitting after Aaron Loup, as the 33 year old has strong reverse splits against lefties over his career.

While Clippard struggled last season, he’s made a series of adjustments to his pitch usage and mechanics that he feels have gotten him back on track. He was terrific in his Blue Jays debut and will have another opportunity to show his stuff Monday, when he’s scheduled to pitch an inning against the Boston Red Sox.

Alburquerque is also making a strong case for himself, striking out seven over his 4.2 innings pitched. He’s allowed just one run — a solo shot off a poorly located slider — over his five appearances, and has walked only one batter. The Blue Jays are asking the 31 year old to utilize a sinker more often, and rely less on his slider, which he used 56 per cent of the time in 2015, his last full season in the majors.

So, a lot of candidates for not very many spots. The Blue Jays are currently planning to roster seven relievers on opening day, although the club has shown a willingness to carry an eight-man bullpen in the past. That could be an option going forward, but isn’t the design right now. Further affecting decision-making is how things shake out in the team’s rotation, as Marcus Stroman continues to recover from right shoulder inflammation and Joe Biagini remains in flux.

There are no guarantees, but it appears Roberto Osuna, Ryan Tepera, Seung-hwan Oh and Aaron Loup are all safe bets to be a part of the opening day bullpen. Danny Barnes is also in a very strong position, but does have a minor-league option remaining which could come into play if the Blue Jays are desperate to preserve depth.

Axford, Santos, Clippard, and Alburquerque, meanwhile, are all in camp as non-roster invitees. Spots on the 40-man roster would have to be opened if any of them were to make the team. Placing one or both of Troy Tulowitzki and Carlos Ramirez on the 60-day disabled list would create room. Beyond that, the Blue Jays would be looking at designated a player for assignment, potentially an outfielder like Dalton Pompey or Dwight Smith Jr.