We're on. The New York Yankees head north Monday for a big three-game series against the Toronto Blue Jays that could decide the American League East title or at least ensure the two teams will battle down to the final weekend. The Jays lead the Yankees by 2.5 games, so a sweep in their favor would all but lock up the division. If the Yankees can pull off the sweep, they'll move back into first place for the first time since Aug. 22.

The pitching matchups:

Monday: Adam Warren versus David Price

Tuesday: Luis Severino versus Marco Estrada

Wednesday: Ivan Nova versus Marcus Stroman

Here are 10 things to watch for in the series:

1. Home runs

These are the two highest-scoring teams in the majors, and both hit a lot of home runs. The Blue Jays lead the majors, but for all the talk about Toronto's big trio of Josh Donaldson, Jose Bautista and Edwin Encarnacion -- each with at least 34 home runs -- the Yankees have hit just eight fewer home runs as a team (202 to the Jays' 210). That power isn't just a result of the short porch at Yankee Stadium, as the Blue Jays and Yankees rank 1-2 in the majors in road home runs.

2. Price against the Yankees' left-handers

This will be Price's fifth start in 2015 against the Yankees -- his fourth since coming over from the Tigers. While the Yankees blasted him for eight runs back in April, his three starts with Toronto have been better (five runs in 19.1 innings). He hasn't allowed a home run to the Yankees all season, and since the trade to Toronto he has allowed just three home runs overall in 62.1 innings, posting a 2.17 ERA. Price still has a pretty good shot at the Cy Young Award; he leads the AL in ERA (2.42) and ranks second in innings (208 1/3) and fourth in strikeouts (212). The Yankees' lineup is heavy with left-handed hitters, but Price has actually had a slight reverse split this season, with lefties hitting .272 against him compared to .220 for right-handers.

3. Yankees have struggled against Blue Jays pitching

The Jays have dominated the season series 11-5, in large part because the Yankees have hit just .221/.286/.357 against Toronto pitching. So it's not just Price who has shut them down. Brian McCann has hit .170 with no home runs in 47 at-bats and Alex Rodriguez has hit .176 with two home runs in 51 at-bats. With Mark Teixeira out, the Yankees will look for those two to provide the power.

Edwin Encarnacion has been on a tear over the past two months, hitting .304 with four home runs in September after batting .407 with 11 homers in August. Tom Szczerbowski/Getty Images

4. How will the Yankees pitch to Encarnacion?

Encarnacion has mashed against the Yankees all season -- .327/.390/.654 with four home runs and five doubles -- and has been Toronto's hottest hitter of late. After hitting .407 with 11 home runs in August, he's hitting .304 with four home runs in September. Check out his splits:

First half: .233/.326/.452

Second half: .352/.443/.709

So how to pitch him? Stay away from fastball counts. Easy to say. In the first half, he had a .710 OPS against fastballs; in the second half, that's climbed to 1.203 as he's hit .378.

5. Severino looks for redemption

The 21-year-old rookie will be making just his ninth major league start, and the one time he didn't produce solid results was Sept. 11 against Toronto at Yankee Stadium, when the Jays scored six runs in 2 1/3 innings and Donaldson and Justin Smoak hit first-inning home runs. Severino relies on his four-seam fastball and slider while mixing in a changeup. His fastball averages 95.4 mph and batters have hit .225 against it. The slider hasn't been the big strikeout weapon you'd think, as opponents are hitting .263/.344/.421 against it with a lower K rate than against his fastball. So even with two strikes, Severino will often stick with the fastball.

6. How much will Joe Girardi ride Dellin Betances and Andrew Miller?

On Saturday, Girardi used Betances for an inning even though the Yankees were up 5-0 on the Mets. He brought Miller in to get the final out of that game even though it wasn't a save situation. On the other hand, that was the only game either has pitched in four days, so both should be relatively rested coming into the Blue Jays series, giving Girardi the option of using them for more than three outs. Betances, who leads major league relievers in innings, has walked nine and allowed three home runs over his past 11.1 innings.

7. Toronto rookie closer Roberto Osuna

The 20-year-old is coming off a blown save against the Red Sox; he gave up three runs to blow a 4-2 lead. After converting his first 16 save opportunities as closer, he has blown two in a row and allowed runs in three of his past six outings. Could he be hitting a wall? He's pitched 64 1/3 innings after throwing just 23 innings in the minors in 2014 and 42 the year before. The Blue Jays say they're not concerned.

8. The return of Stroman

The little righty with the multitude of pitches will be making his third start in his remarkable return from a torn ACL in spring training. He's won his first two outings, although he has struck out just five in 12 innings. His fastball velocity is down 1.1 mph from last season as he's still building up innings. Obviously, the sample size is small, but compared to 2014 he's throwing his fastball a little more, his curveball more and his slider less. Oh, he also has a changeup, cutter and sinker. In other words, not pitching much in 2015 could be to his advantage as the Yankees won't have a good scouting report to rely upon.

9. No Troy Tulowitzki

In Tulo's absence, the Jays have shifted Ryan Goins from second to shortstop while starting Cliff Pennington at second. The good news is that it means Toronto's defense up the middle remains strong. Goins is a tremendous shortstop and Pennington has been a good defender at both short and second in his career.

10. Dustin Ackley

Just to rub salt in the wounds of Mariners fans. He had a big three-run homer Sunday to help the Yankees rout the Mets 11-2, which could draw him another start or two at second base in this series.