2017 record: 93-69 (first place; lost in ALDS)
Key additions: After jumping at the opportunity to bring back first baseman Mitch Moreland on a two-year, $13 million contract that proved a bit above market value, the Red Sox waited for the rest of their business. First, it was a two-year deal to bring back utility man Eduardo Núñez. Then it was the best free-agent slugger on the market — J.D. Martinez. After hitting .303 with a 1.066 OPS and 45 home runs in 119 games last year with the Detroit Tigers and Arizona Diamondbacks, Martinez always was the type of player Boston needed to add to its balanced but power-starved lineup without David Ortiz.
Key losses: Boston claimed Doug Fister from the Los Angeles Angels in June to fill injury holes in its rotation, but will have to find other depth options after he signed a one-year deal with the Texas Rangers. The Red Sox’s other deadline acquisition last summer, reliever Addison Reed, signed a two-year deal with the Minnesota Twins.
X-factor: Mookie Betts
After finishing second in the 2016 American League Most Valuable Player voting while batting .318/.363/.534 with 31 home runs, Betts never got into the same groove in 2017. He ended the year batting .264/.344/.459 with 24 home runs. It was a fine season, but Betts, shortstop Xander Bogaerts and now third baseman Rafael Devers were expected to continue their offensive development to the point where the Red Sox wouldn't miss Ortiz. Now, with a slugger hitting behind him again in Martinez, maybe Betts will get back to his near-MVP form.
Outlook: Consecutive division titles and 93-win seasons weren’t enough to save manager John Farrell's job, and now it's on Alex Cora to jump-start what should be one of the game's best offenses. If the highly paid pitching staff of David Price, Rick Porcello, Chris Sale and Drew Pomeranz can hold up its end of the bargain, the Red Sox should do their part in making the top of the division a clash of financial titans between themselves and the New York Yankees.
Tampa Bay Rays
2017 record: 80-82 (third place)
Key additions: If the Rays added anything this winter, it was in return for massive pieces going the other way. The most noteworthy addition is first baseman C.J. Cron, who became surplus for the Angels and is a useful power bat with three years of team control remaining. They added former All-Star Carlos Gómez and veteran Denard Span to their outfield, and prospect Christian Arroyo to their infield, but the latter two at a great cost.
Key losses: Most of the Rays' modest additions this offseason came at the expense of what they lost, starting with third baseman Evan Longoria, the face of their franchise for the past decade. He was dealt to the San Francisco Giants in a salary dump for Span, Arroyo and two other prospects just before he'd have been able to veto a trade. Outfielder Corey Dickerson was an All-Star a season ago and ended up hitting .282 with 27 home runs, but was designated for assignment to make room for Cron on the 40-man roster. And right-hander Jake Odorizzi was sent to the Minnesota Twins in a February trade, leaving the Rays rotation short-handed. They also traded outfielder Steven Souza after he hit 30 homers last season and didn't bring back first baseman Logan Morrison, who hit 38 home runs and signed with the Twins. Right-hander Alex Cobb also left via free agency.
X-factor: Chris Archer
One of the most entertaining players in the game, Archer will have to be much more than that for this season to be a success. He made his second All-Star Game in 2017, but a tough September brought his final ERA up to 4.07, over 4.00 for the second straight season. He's always been teetering that line of being really good and great, and on a team bereft of much to hope for in 2018, seeing Archer put together a Cy Young-worthy season would be a bright spot.
Outlook: From their odd plans for a four-man rotation with a bullpen day built in, to jettisoning the bulk of their returning offensive threats, the Rays seem to be in one of the ebbs of their competitive waves. They'll have the pitching to remain competitive, but that could be the ceiling.
2017 record: 76-86 (fourth place)
Key additions: Toronto's main offseason acquisition was from the St. Louis Cardinals, who had a crowded outfield and sent Randal Grichuk north to man right field in the post-José Bautista era. They also added veteran outfielder Curtis Granderson and a nice buy-low infielder from the Cardinals in shortstop Aledmys Díaz, who had a stellar 2016 season but struggled some in 2017. Otherwise, they signed left-handed starter Jaime García and tried to rebuild their bullpen with Seung Hwan Oh and low-cost minor league deals for Tyler Clippard, Craig Breslow, John Axford and Jake Petricka.
Key losses: The player perhaps most synonymous with the Blue Jays' recent success — Bautista — didn't return for 2018. Bautista's one-year pillow contract in 2017 didn't yield much for either side. Elsewhere, utility infielder Ryan Goins wasn't tendered a contract and flirted with the Orioles before signing with the Kansas City Royals.
X-factor: Josh Donaldson
A former MVP won't exactly come out of nowhere to make or break a club's season, but Donaldson can use a great year as much as his club needs one from him. He's a key member of the impressive free-agent class of 2019, and hit 33 home runs with a .944 OPS despite playing just 113 games because of a calf injury. But a full season of the All-Star-caliber offense that Donaldson has brought since 2013 will make his free agency much more attractive, considering he'll be 33 in December. Even with an inevitable decline, he'd like that decline to be from a high point.
Outlook: The Blue Jays got younger where they could, and bring back a strong rotation with Marcus Stroman, Marco Estrada, J.A. Happ and Aaron Sanchez all remaining in fine form, so expectations can't be too low. There's just a lot of uncertainty as to what it will all add up to. They went to the American League Championship Series twice in a row before missing the playoffs in 2017, and if the Orioles can call 2017 an aberration and say they'll contend again, why can't the Blue Jays?
New York Yankees
2017 record: 91-71 (second place; lost in ALCS)
Key additions: No team made a bigger acquisition this offseason than the Yankees bringing Giancarlo Stanton in from the Miami Marlins after his major league-best 59 homer season. He makes one of the most powerful lineups in the game even more threatening. Around him, the Yankees filled whatever could be considered a hole without breaking the bank. They traded for infielder Brandon Drury to fill in as a cost-controlled third baseman, and Neil Walker signed a cut-rate $4 million deal to play first, second and third. Both are bridges to prospects, but they're good ones.
Key losses: Drury and Walker will fill in for two regulars from last year's playoff run: Todd Frazier and Starlin Castro. Castro went to the Marlins in the Stanton deal, and Frazier signed with the crosstown Mets. Otherwise, the Yankees kept their rotation intact after Masahiro Tanaka decided not to opt out of his contract and CC Sabathia re-signed. They didn't have Michael Pineda for the second half of last season because of injury anyway, but he signed with the Minnesota Twins in free agency.
X-factor: Aaron Judge
Can he do it again? With Stanton around and another year of development for the likes of Gary Sánchez and Greg Bird, Judge might not ultimately have to. But if he can repeat last year's league-best 52 home runs while posting 8.1 wins above replacement, this team will be a nightmare. Judge's streakiness came to the fore a bit in 2017, and while he was able to adjust for a strong September, teams are going to try to do anything they can to find a way to get him out. If he can keep it up, he'll be a superstar for a long time.
Outlook: The Yankees were ahead of schedule in knocking out the Cleveland Indians and making the ALCS last season, and when a team does that, the hardest thing to do is to not fall backward in pursuit of that. The champion Houston Astros had it happen before winning last season. But the Yankees improved as much, if not more than any other team in the league this winter, and have assembled as imposing an offense as any in the game. Not making the playoffs would be a disaster, but given the expectations on this team, anything short of a World Series might be seen as such for new manager Aaron Boone.