In the past six years, all five American League East teams have won the division.

Oh, the parity.

Or should we say the mediocrity? Only one of those teams – the 2013 Red Sox – has reached the World Series.

Boston finished last in 2014 and 2015, but because of the aforementioned mediocrity … er, I mean parity, the Red Sox are considered contenders in 2016.

Many predictions have Boston winning the division – something prognosticators said last year, too.

There is certainly a lot to like about the acquisitions of pitchers David Price and Craig Kimbrel and the emergence of Mookie Betts and Xander Bogaerts.

But how did defending champion Toronto fall off the radar?

Beware of the Blue Jays. Sure, Toronto lost two starting pitchers in Price (free agency) and Mark Buehrle (retirement, for now), but last I checked, power hitters Jose Bautista, Josh Donaldson and Edwin Encarnacion are still in the lineup. Plus, Toronto also features first baseman Chris Colabello and shortstop Troy Tulowitzki, the latter giving the Blue Jays one of the best up-the-middle defenses in the division.

Marcus Stroman is the new staff ace. He missed most of last season, but finished with a 4-0 record with a 1.67 ERA. And Stroman is 4-0 with a 1.26 ERA in four career starts against Boston.

The rest of the rotation – Marco Estrada, R.A. Dickey, J.A. Happ (free-agent signing) and Aaron Sanchez – could be enough for Toronto to repeat, especially with the Blue Jays’ offensive might.

How good are the Blue Jays? Boston will find out soon enough. After the opening series in Cleveland, the next 14 games for the Red Sox are in the division, including seven against Toronto.

The New York Yankees were a wild-card team last year, with surprising contributions from the aging trio of Mark Teixeira (.906 OPS), Alex Rodriguez (.842) and Carlos Beltran (.808). But Rodriguez is now 40, and next month Beltran turns 39 and Teixeira 36. Can they keep it up?

Then there’s sometimes-fragile outfielder Jacoby Ellsbury, who missed 51 games last year and has been dealing with an injured wrist this spring.

The starting rotation had a 4.25 ERA last year, and only the emergence of prospect Luis Severino offers hope that New York will be better. One-time ace CC Sabathia was 6-10 last year, and this spring has a 5.84 ERA.

New York’s chances rest on the back end of its bullpen. Andrew Miller, Dellin Betances and Aroldis Chapman should be able to protect any lead (after Chapman serves a 30-day suspension under MLB’s new domestic violence policy).

The Tampa Bay Rays rarely look formidable – they ranked 14th in the league last year in runs scored. But the Rays are always considered potential contenders because of their starting rotation – the American League’s best last year. Ace Chris Archer looks to be on the verge of stardom, while Jake Odorizzi, Drew Smyly, Matt Moore and Erasmo Ramirez complete an impressive rotation.

Speaking of starting pitching, it could be the continued undoing of the Baltimore Orioles, and why most recent predictions have Baltimore finishing last. Baltimore’s rotation ranked 14th in the league last year, and the Orioles lost their most reliable starter, Wei-Yin Chen, to free agency.

If Chris Tillman can bounce back from his 4.99 ERA last year and if Ubaldo Jimenez ever finds consistency, the Orioles could be in business. Of course, Manager Buck Showalter always squeezes everything he can out of the bullpen, keeping Baltimore competitive.

A lineup that includes Manny Machado and Chris Davis could be dangerous. Additions Mark Trumbo, Pedro Alvarez and Hyun-Soo Kim (from South Korea) might help.

Yes, it’s possible that any of the five teams could win the division.

It’s a good bet, though, that the Blue Jays will repeat.

My picks: 1. Toronto 90-73; 2. Boston 87-75; 3. New York 84-78; 4. Tampa Bay 80-82; 5. Baltimore 78-84.Twitter: ClearTheBases