TORONTO -- The Toronto Blue Jays enjoyed a strong opening month before slipping in May. A road loss to the New York Mets on Tuesday will leave the Blue Jays at the .500 mark.

Here's a look at some of the storylines over the first quarter of the season:

Rotation deflation

The Blue Jays' starting rotation was supposed to be one of the team's strong points this season. It has been one of its biggest disappointments.

Marcus Stroman's numbers have been abysmal, newcomer Jaime Garcia hasn't fared much better and Marco Estrada has been mediocre. Joe Biagini made a few spot starts and has disappointed.

J.A. Happ and Aaron Sanchez have been decent but are both sporting earned-run averages nearly a run over their career norms.

For Toronto to have any chance of contending for a playoff spot, the starters must go deeper in games.

Prospect capital

The Blue Jays boast one of the sport's top prospects in Vladimir Guerrero Jr., who is enjoying a monster season with the double-A New Hampshire Fisher Cats.

It remains unclear when or if he'll get a call-up this season. In the meantime, some of Toronto's other intriguing young prospects have had a taste of the big leagues.

Infielder Lourdes Gurriel Jr. showed flashes of his potential before being sent down to triple-A Buffalo over the weekend.

Teoscar Hernandez has hit some tape-measure homers since his recall from the Bisons in mid-April. Anthony Alford, Dalton Pompey and Dwight Smith Jr., have also had some looks in the outfield.

COLD CORNER

The shoulder woes that limited third baseman Josh Donaldson in spring training have been a concern this year.

The 2015 American League most valuable player tried to battle through a dead arm issue in April before spending a month on the disabled list. His cross-diamond throws from third base have been significantly weaker than normal at times.

Donaldson, a three-time all-star, has also seen drops in his offensive averages (.239 BA, .320 on-base percentage, .467 slugging percentage) and his WAR (wins above replacement) has tumbled to 0.5.

The 32-year-old slugger is slated to become a free agent at the end of the season.

Struggles and surprises

A few Toronto players have been pleasant surprises at the plate while others have yet to get on track with the bat.

Backup catcher Luke Maile has taken advantage of his opportunities and provided some pop at the plate with a .317 average and .508 slugging percentage.

Centre-fielder Kevin Pillar, who's known more for his defence than his offence, is batting .308 and leads the team in hits (48), doubles (17) and runs (25).

Among the disappointments, designated hitter Kendrys Morales has struggled mightily after hitting 28 homers and driving in 85 runs last year. He has gone yard just three times in 28 games and is batting a feeble .154.

Russell Martin is batting just .172 while injured outfielder Randal Grichuk has managed only seven hits in 66 at-bats (.106).

Relief needed

The absence of closer Roberto Osuna has created a big hole in an already overtaxed bullpen.

Osuna's potential return date is uncertain. He was placed on administrative leave by Major League Baseball last week after being charged with assault.

Tyler Clippard has been given the ball in the ninth inning and Seung Hwan Oh, Ryan Tepera and John Axford could also close if needed.

Clippard, Oh and Axford have yet to record a loss this season. All three players have earned-run averages under 1.50.