Good teams are typically strong up the middle, so it should come as no surprise that the American League East is loaded with quality players at second base and shortstop. The Rays are the defending AL champions. The Yankees are reloaded and ready for another run at the postseason. The Blue Jays geared up this offseason to battle those two atop the division. The Red Sox have bolstered their roster, and the Orioles are improving with an eye on the future.

At these two key spots, the AL East clubs have made a few changes, brought back some familiar faces, kept a bunch of talented players in place and watched the development of some potential future stars who could make an impact later this year.

Here's a look at what we know, and what we don't, about the middle-infield situations around the AL East.

Blue Jays
The known: Bo Bichette and Marcus Semien give the Blue Jays loads of offensive potential up the middle, and as long as both stay healthy, each should cruise past 150 games played in 2021. Semien comes to Toronto on a one-year, $18 million deal and will need some time to adjust back to second base after years playing primarily shortstop, but that should be handled easily in Spring Training. The veteran started slowly in 2020, but he was one of baseball's top players in '19 when he hit .285 with 33 home runs and an .892 OPS, finishing third in AL MVP Award voting. He'll be a great mentor for the 22-year-old Bichette, who is entering a pivotal season in his development. Bichette played in 46 games after debuting in '19 and just 29 in his injury-shortened '20, so while the talent is undoubtedly there, the young shortstop will be challenged to carry his production and high-energy style through a full Major League season.

The unknown: Barring an injury, this middle-infield picture is simple. If Bichette needs a day, Semien can easily slide over. When Semien needs a day, Cavan Biggio can handle second. Things get more complicated with the supporting cast if the Blue Jays need someone to cover more than a month, though. With top prospects Austin Martin and Jordan Groshans likely still a year or more away, the club brought back veteran infielder Joe Panik on a Minor League deal with an invitation to Spring Training. Panik should have every opportunity to crack the roster as that reserve infielder, given his ability to play second and third. Beyond Panik, Toronto has the versatile Santiago Espinal, who impressed the organization with his 2020 debut. -- Keegan Matheson

Orioles
The known: One of the first moves the Orioles made this winter was flipping Jos¨¦ Iglesias to the Angels for prospects, opening a hole at shortstop they then filled by signing veteran Freddy Galvis to a one-year, $1.5 million deal in late January. Galvis figures to work most consistently with double-play partner Yolmer Sánchez, whom the O's claimed off waivers in November before releasing Hanser Alberto during the arbitration process. A Gold Glove winner as recently as 2019 with the White Sox, S¨¢nchez is a switch-hitter who can also play short and third if needed. But he profiles as the everyday second baseman at this point, with Pat Valaika and Richie Martin slotting behind as utility options.

The unknown: If Galvis, 31, remains durable, he'll be at shortstop every day. S¨¢nchez has more of an inside track at second, but he could be challenged, mainly by right-handed options like No. 19 prospect Jahmai Jones and No. 26 Rylan Bannon (or even No. 22 prospect Ryan McKenna, a natural outfielder the O's might try at second). Besides from Valaika and Martin, other utility options who could see run at second include Stevie Wilkerson and Ram¨®n Ur¨ªas, especially if S¨¢nchez struggles offensively. Nobody on the roster is more suited than Martin to be the backup shortstop, but he'll miss at least the first month of Spring Training recovering from right wrist hamate surgery. -- Joe Trezza

Rays
The known: Heading into Spring Training, the Rays are set up the middle with Willy Adames back at shortstop and Brandon Lowe holding down second base. They'll be able to back up those two everyday players with Joey Wendle, who can play second or shortstop when he's not at third base, and Mike Brosseau has experience at second as well. Both starting middle infielders will have something to prove, however, as they're coming off rough performances in the postseason following excellent regular-season showings at the plate. Adames slashed .259/.332/.481 with eight homers and 1.9 bWAR in the regular season, and then posted a .505 OPS in the playoffs. Lowe led the team with a 2.4 bWAR in the regular season before batting just .118 with 28 strikeouts in 82 postseason plate appearances.

The unknown: When will it be Wander Franco's turn? All eyes will be on MLB Pipeline's No. 1 prospect from the time Spring Training begins until the moment he takes the field with the Rays. The switch-hitting shortstop will make a big impact at the plate no matter where he plays, so it's worth wondering if Tampa Bay will expand his defensive profile by bouncing him around the infield this spring. But given its returning personnel and the fact that he'll only be 20 years old this season, there's no reason to rush him if he needs more time in the Minors. Whenever Franco is ready, how will the Rays adjust their infield to make room? Could Adames be traded this summer? The club boasts even more upper-level prospect depth up the middle with speedy second baseman Vidal Bruj¨¢n and slick-fielding shortstop Taylor Walls, so it has options. -- Adam Berry

Red Sox
The known: In Xander Bogaerts , the Red Sox have one of the best and steadiest all-around shortstops in baseball. Bogaerts is an absolute rock at the plate, a given to hit for average and power every season. He is also durable and never asks for a day off, even though manager Alex Cora will protect him by giving him his share. As steady as Bogaerts has been the last several seasons, that's how unsteady a situation the Sox have had second base since Dustin Pedroia was injured in 2017. The hope is that the signing of Enrique Hernández will fix that. A super-utility player most of his career, Hern¨¢ndez is going to get a crack at holding down one position.

The unknown: Hern¨¢ndez has started 132 games at second base in his career, and the Red Sox could be looking for him to start that many this season. In other words, it will be a work in progress to see if he is up the task. The good news is that Boston has plenty of options to mix and match at the position, including Marwin Gonzalez, who has reportedly agreed to a one-year deal, and Christian Arroyo, who got some time at the position late last season. The worst-case scenario for the Red Sox would be for Bogaerts to suffer an injury. Though they have players who can back up at the position -- including Gonzalez and Hern¨¢ndez -- it would be a lot to ask anyone in the organization to play there for an extended period. Jeter Downs, the team's No. 1 prospect as rated by MLB Pipeline, could be given a shot in that scenario. -- Ian Browne

Yankees
The known: The move that the Yankees absolutely had to make this offseason was re-signing second baseman DJ LeMahieu, the AL's reigning batting champion and their most valuable player over the past two seasons. With LeMahieu locked in on a six-year, $90 million deal, the Bombers boast one of the sport's best all-around hitters atop their lineup, setting the tone for the power bats behind him. A three-time Gold Glove Award winner, LeMahieu solidifies the infield defense up the middle, teaming with Gleyber Torres as one of the circuit's more promising double-play combinations.

The unknown: Torres' star remains bright, but his ability to stick at shortstop slipped into question last year as the 24-year-old struggled defensively and didn't hit for much power. The Yankees believed that Torres was not in prime physical condition upon reporting to Summer Camp and needed several weeks to regain his form, but general manager Brian Cashman said he thinks Torres was playing near the peak of his abilities by the postseason. The Bombers can survive if Torres is merely adequate with the glove, especially if he slugs the ball like in 2019. That version of Torres was missing for a large swath of '20. -- Bryan Hoch