The offseason gives each MLB front office an extended opportunity to pinpoint its roster’s biggest weaknesses and address them.

With the current offseason winding down, here’s a position-by-position look at which teams made the most substantial improvements in areas that were major weak spots for them a year ago.

Catcher: Cardinals

What happened: With Cards legend Yadier Molina slumping to career worst offensive levels in his final MLB season and Andrew Knizner supplying little offense in his own right, St. Louis’ catching group posted the third-lowest OPS (.552) in the Majors, better than only the Pirates and Guardians. Knizner’s .601 OPS was actually the highest among the four players who started a game behind the plate for the Cards in 2022, and the quartet of Molina, Knizner, Iván Herrera and Austin Romine combined for -0.6 wins above replacement, per FanGraphs.

What's changed: The Cardinals went out and signed one of the top hitting catchers in the game, inking free agent Willson Contreras to a five-year, $87.5 million deal. Contreras, the longtime starting catcher for the rival Cubs, has four 20-plus home run seasons on his resume as well as a lifetime .808 OPS, including .815 in 2022. Steamer, one of baseball’s premier projection systems, predicts the 30-year-old will produce 3.2 WAR in 2023, tied for the seventh-best projection among catchers.

First base: Astros

What happened: After winning the AL batting title in 2021, Yuli Gurriel struggled to the tune of a .242/.288/.360 slash over 146 games last season, producing -0.9 WAR. Houston first basemen recorded a collective .656 OPS, the sixth-lowest mark in MLB.

What’s changed: The Astros signed José Abreu to a three-year, $58.5 million deal in free agency to replace Gurriel. While the 2020 AL MVP had a career-low 15 homers last season, he still produced a 133 OPS+ and 3.9 WAR while slashing .304/.378/.446.

Second base: Mariners

What happened: The M’s acquired Adam Frazier from the Padres in November 2021 and installed him as their starting second baseman, but the veteran posted a .238 average -- 67 points lower than he hit the previous season -- with a .612 OPS and 1.1 WAR over 156 games, including 113 starts at the keystone. With Abraham Toro (.563 OPS) also garnering 39 starts at the position, Seattle second basemen had the third-lowest OPS (.607) in MLB.

What’s changed: With Frazier reaching free agency, the Mariners made another offseason trade for a second baseman, sending outfielder Jesse Winker and Toro to the Brewers for Kolten Wong in December. Wong isn’t a great hitter, and he’s coming off a down year on defense after winning Gold Glove Awards in 2019 and 2020. However, Steamer projects him for a .709 OPS and 2.4 WAR in 2023, which would be a considerable improvement over the team’s second-base production from 2022.

Third base: Nationals

What happened: The majority of Washington’s third-base starts in 2022 went to veteran Maikel Franco, who was released last August and is now a member of the Tohoku Rakuten Golden Eagles in Japan’s Nippon Professional Baseball. Nats third basemen posted a .613 OPS, third lowest in MLB.

What’s changed: After the Tigers non-tendered Jeimer Candelario, the Nats signed the 29-year-old to a one-year deal in December. Candelario’s projections aren’t eye-popping, but a .240 average, 17 homers, a .717 OPS and 1.5 WAR would be a clear upgrade compared to what Washington got from its third basemen in 2022. During an offseason when there weren’t many impactful third basemen to be had in free agency, this stands out as the biggest hot-corner improvement any team made relative to 2022.

Shortstop: Phillies

What happened: The Phillies opened last season with Didi Gregorius as their regular shortstop, but after the veteran recorded one homer and a .567 OPS over his first 232 plate appearances, Philadelphia released him on Aug. 4 and handed the starting job to rookie Bryson Stott. Though the youngster was better than Gregorius, he didn’t exactly set the world on fire, finishing the regular season with 10 homers and a .653 OPS.

What’s changed: Trea Turner, anyone? The Phillies made one of the biggest splashes of the offseason when they signed the superstar shortstop to an 11-year, $300 million contract. As a result, they’ve gone from having a below-average shortstop situation to one of the best. Turner, who hits for average and power and is one of the fastest players in baseball, has a 4.7 WAR projection for 2023.

Outfield: Padres

What happened: Before the Padres swung a blockbuster deal for Juan Soto at the Trade Deadline, their outfield was a below-average offensive unit that regularly featured Trent Grisham in center, Jurickson Profar in left and either Wil Myers or Nomar Mazara in right. After the trade? Only slightly better.

What’s changed: Having Soto for a full season would have made some difference on its own, but the Friars needed to do more to improve their outfield production, especially with Profar and Myers both reaching free agency. After an 11th-hour push for Aaron Judge fell short, the Padres went with an outside-the-box option to address their outfield, signing shortstop Xander Bogaerts to an 11-year, $280 million contract. San Diego, of course, already had a shortstop in Fernando Tatis Jr., but the 24-year-old will now be patrolling the outfield with Soto and Grisham. In terms of WAR, Soto is Steamer’s top projected player at 7.1, and Tatis is tied for eighth at 5.5. The Padres also signed Matt Carpenter, who could see time at the outfield corners, and Adam Engel.

Starting rotation: Rangers

What happened: The Rangers stunned the baseball world with their offseason spending spree after the 2021 season, signing infielders Corey Seager and Marcus Semien and right-hander Jon Gray for a combined $556 million and adding Martín Pérez on a one-year deal. But despite getting a career year from Pérez and a solid, albeit injury-plagued, season from Gray, the Rangers’ rotation was among the worst in the Majors. Dane Dunning, Glenn Otto, Taylor Hearn, Cole Ragans, Spencer Howard, Kohei Arihara and Dallas Keuchel combined to make 92 starts with a 5.42 ERA, and the Rangers recorded their sixth straight losing season at 68-94.

What’s changed: Texas invested heavily in its rotation, bringing back Pérez with a one-year qualifying offer before signing two-time Cy Young Award winner Jacob deGrom, Nathan Eovaldi and Andrew Heaney in free agency and trading for Jake Odorizzi. There’s a lot of risk involved given the injury histories and ages of the pitchers they acquired, but there’s no denying the upside here. If this experiment works, the Rangers could have the best rotation in the sport.

Bullpen: Red Sox

What happened: Though they found a gem in John Schreiber and had success converting Tanner Houck to a late-inning role, the Red Sox otherwise had little go right with their relief corps in 2022. Boston had MLB’s fifth-highest bullpen ERA (4.59) and tied for last in the percentage of inherited runners who came around to score (40%).

What’s changed: The Red Sox’s offseason left a lot to be desired, losing Bogaerts to the Padres and largely staying away from pursuing other elite free agents. But at the very least, Boston did upgrade its bullpen significantly with the additions of Kenley Jansen and Chris Martin, who are expected to serve as the team’s closer and setup man, respectively. The Red Sox also signed left-hander Joely Rodríguez and added another left-hander, Richard Bleier, from the Marlins in a trade for Matt Barnes. Boston’s bullpen now projects to be a middle-of-the-pack unit instead of one of MLB’s worst.