By Michael Hurley, CBS Boston

BOSTON (CBS) — It’s been a while since we’ve had a mid-May baseball series worth our attention. So perhaps we’re a little rusty here in recognizing the big ones.

But this upcoming three-game set for the Red Sox against the Blue Jays? It feels like a big one.

Obviously, the division won’t be won or lost this week down in Dunedin, which remains Toronto’s temporary home until they move to Buffalo in June. But with a surprising 25-17 start to the season, the Red Sox have turned a season with very low expectations into one where they’ve suddenly become the hunted in the AL East.

Entering Tuesday’s series opener, the Blue Jays are just 1.5 games behind the first-place Red Sox. The Blue Jays swept the Braves in Atlanta last week before taking two of three in Philadelphia to close up that gap. Boston lost two of three at home to the A’s before winning two of three — but losing the sweep in the ninth inning on Sunday — against the Angels.

With a whole summer left to play, the top spot in the AL East is sure to change hands several times. (Tampa Bay is just two games back, with the Yankees a half-game behind the Rays.) But for this week, the Red Sox will have absolutely no interest in ceding control of division, a spot they’ve maintained since April 10.

SEASON SERIES

The Red Sox and Blue Jays have met just twice already this season. The Red Sox won the first of that two-game set at Fenway on April 20 by a score of 4-2. The Red Sox did all of their offensive damage in the fourth inning against Hyun Jin Ryu, first with a three-run home run off the bat of Xander Bogaerts, then with a two-out triple by Bobby Dalbec to score the fourth run of the inning. Eduardo Rodriguez allowed two runs over six innings, Matt Andriese and Adam Ottavino each picked up a hold, and Matt Barnes closed the door with a 14-pitch ninth inning.

The Blue Jays won the next night, jumping all over Garrett Richards to the tune of four runs — off six walks and four hits — in 4.2 innings. The Red Sox clawed back into the game, cutting it to a 4-3 Toronto lead after eight innings. But Josh Taylor surrendered a pair of runs in the top of the ninth inning, and the 6-3 score held for the final.

That win got the Blue Jays to 8-10 on the young season, and they’ve gone 14-7 since.

THE STANDINGS

1. Boston, 25-17
2. Toronto, 22-17, 1.5 GB
3. Tampa Bay, 23-19, 2.0 GB
4. NY Yankees, 22-19, 2.5 GB
5. Baltimore 17-23, 7.0 GB

Game 1

Tuesday, May 18, 7:37 p.m.
Eduardo Rodriguez (5-1, 4.15 ERA) vs. Hyun Jin Ryu (3-2, 2.95 ERA)

A pitching rematch from April 20, this one features the Blue Jays’ Opening Day starter against the man who would have been the Red Sox’ Opening Day starter, if not for an arm issue springing up late in spring training.

Rodriguez has been a bit shaky this month, allowing nine runs in 16 innings in his three starts since May 1. Opponents are hitting .338 against him during that stretch. Some of that might be bad luck (opponents have a  .426 BAbip in those three starts), but the end result is an ERA that’s climbed from 3.38 after that win over the Blue Jays to 4.15 after last week’s loss to Oakland.

Ryu missed some time since that loss in Boston, leaving his next start after 3.2 innings with a glute strain. He gave up four runs in five innings when returning vs. Oakland on May 6, but allowed just one run over seven innings in his last outing in Atlanta.

Game 2

Wednesday, May 19, 7:37 p.m.
Garrett Richards (3-2, 3.89 ERA) vs. Ross Stripling (0-2, 5.91 ERA)

The last time Richards faced the Blue Jays, it honestly looked like he might not be long for the Boston Red Sox. He was sitting at 0-2 with a 6.48 ERA and seemed like not the best fit for Boston. But he’s been tremendous since then, going 3-0 with a 2.16 ERA in four starts since April 27. He shut down the A’s last week at Fenway, pitching six shutout innings to drop his ERA under 4 for literally the first time all year. (He allowed a run before recording an out in his first start, which ended with six earned runs over two innings.)

Stripling has had a tough go of it for Toronto, lasting just 4.1 innings per start. He faced the Red Sox once last year, a game in which he allowed three runs in 4.1 innings and took the loss. The 31-year-old righty had a 3.51 ERA with the Dodgers from 2016-19, but he has an unsightly 5.86 ERA since the start of last season.

Game 3

Thursday, May 20, 7:37 p.m.
Nick Pivetta (5-0 3.16 ERA) vs. Steven Matz (5-2, 4.29 ERA)

In 10 starts for the Red Sox, Nick Pivetta has yet to lose a game. He was 2-0 with a 1.80 ERA after being acquired by Boston last year, and he’s 5-0 with a 3.16 ERA this year. His 1.172 WHIP this year is significantly better than his career mark of 1.405, as the 28-year-old is seemingly putting it all together. He’s allowed two or fewer runs in six of his eight starts this year, averaging 5.1 innings per outing.

Matz, meanwhile, is rebounding nicely from a disastrous 2020 season for the Mets. He was 0-5 with a 9.69 ERA and 1.696 WHIP in nine appearances (six starts) last year. The offseason trade to Toronto has helped Matz, who’s allowed one or zero runs in half of his starts this year. He’s coming off a nine-strikeout performance over five shutout innings against the Phillies last week.

The Mood

If the Red Sox had any lingering sadness from Sunday’s ninth-inning loss to the Angels, they had a funny way of showing it. The team showed up for their road trip Monday decked out in full beach attire.

At the very least, a very loose ballclub will be showing up to play Tuesday night in Dunedin.