NL East Stock Watch: Which team is having the best winter?

So far this offseason, no division has been as aggressive in the aggregate as the five teams in the National League East. Whether spending big on free agents, making trades for star players or promising to spend stupid money, the Nationals, Mets, Braves and Phillies are all looking to make the playoffs this season, and even the Marlins are making news by entertaining potential trades for star catcher J.T. Realmuto.

Let's take a look at what the teams have done so far, how that has impacted their 2019 playoff odds since the end of the season -- with an assist from FanGraphs' Dan Szymborski -- and what they might still do to help themselves even further.

  Washington Nationals

The Nationals signed this winter's best available free-agent starting pitcher in Patrick Corbin. They shored up their catching spot, their weakest position, by signing Kurt Suzuki and trading for Yan Gomes, and they added bullpen help by singing Trevor Rosenthal and trading for Kyle Barraclough. The team might be losing Bryce Harper to free agency, but the Nationals are nevertheless positioning themselves very well to get back to the playoffs next season. They moved Tanner Roark to Cincinnati at the winter meetings, but gaining Corbin is still a big plus for the rotation.

According to Dan Szymborksi's ZiPS projections, no team in baseball has improved itself as much as the Nationals, going from an 85-win team to an 89-win team and increasing their playoff odds from 50.6 to 63.6 percent with their moves so far. They're also the narrow favorites to win the division, holding little more than a 1 percent advantage over the Braves, 36.3 to 34.9 percent.

As far as what's left to do, although the Nats haven't closed the door on a Harper return, top prospect Victor Robles looks ready to join Juan Soto in the outfield, and Adam Eaton should be back from injury. The team doesn't need to do too much more, but there are a glut of quality second baseman available, so expect them to nab somebody. If they get really ambitious, locking up Anthony Rendon long-term wouldn't be the worst idea, as the star third baseman will be eligible for free agency after next season.

  New York Mets

ZiPS has the Nationals as the team that has improved the most since the end of October, but right on their heels are the Mets. New general manager Brodie Van Wagenen has wasted no time in trying to transform the team by making the biggest, most complex trade of the winter so far. Much is made of the money that is owed to Robinson Cano, but he's still a solid player, and Edwin Diaz was one of the best relievers in baseball last season.

According to ZiPS, the Mets projected as an 82-win team with a 31.2 percent chance at the playoffs before the big trade, but they have moved all the way up to 86 wins and a 44.1 percent chance of reaching October. ( Editor's note: And Thursday's return by free agent and former Met Jeurys Familia nudges that number a little higher.) And they might not be done as far as major moves. Adding a center fielder might make the most sense for Mets, but rumors have them particularly connected to Realmuto. If the Mets were to land the Marlins catcher, who is projected for roughly 4.0 WAR in each of the next two seasons, the Mets would jump up another couple wins while pulling roughly even atop the division. That rosy scenario requires the club to make that trade while keeping Noah Syndergaard, which would probably be best if the team wants to get to the playoffs next season.

  Atlanta Braves

After the Nationals and Mets, it is the Yankees and Cardinals who have made the biggest moves in terms of playoff odds, but the Braves are still in baseball's top five, thanks to their one-year deal with third baseman Josh Donaldson. The former MVP has big bounce-back-season potential and played very well down the stretch with Cleveland. If he is anywhere close to the player he was before last season, he will help anchor a lineup that already has a star in Freddie Freeman and a potential superstar in Ronald Acuna. The team also added Brian McCann behind the plate after Kurt Suzuki departed.

In total, Atlanta has added three wins and gone from a 51.5 percent chance to return to the playoffs to 62.5 percent, and like their rivals, the team probably isn't finished making impact moves. The Braves could add free-agent outfielder Michael Brantley or trade from their deep farm system for another corner outfielder. Adding another starting pitcher is probably in order, and with a farm system full of promising young arms, no available veteran pitcher on the block is going to be out of their reach. In another month, the Braves might be back where they were at the end of the season: on top of the division.

  Philadelphia Phillies

The Phillies haven't quite gotten the same impact from their moves, as losing OBP machine Carlos Santana from the lineup minimizes some of their gains. Even so, getting Rhys Hoskins out of the outfield will help their defense significantly. Jean Segura is an upgrade over J.P. Crawford at shortstop. Andrew McCutchen will be a big help in solidifying the production from the outfield, and Juan Nicasio could help in the pen as well. Of the four main rivals within the NL East, the Phillies probably have the most to do to solidify their bid for contention.

So far, the Phillies have moved from an 80-win club to an 83-win team on paper, according to ZiPS. That translates into an improvement of their playoff odds from 20.8 to 26.9 percent. That's the seventh-biggest gain so far this offseason, but it ranks fourth in the division.

But saving the best for last, the Phillies are in on both of baseball's top two free agents this winter. Signing Bryce Harper or Manny Machado would put the team right near the top of the division. The Phillies could use one more outfielder and one more starting pitcher, and with the low payroll they have had the past few years, they can afford to make a huge jump with their budget and erase the bad feeling left over from their fade at the end of last season.

  Miami Marlins

Unlike the rest of the division, the Marlins haven't done much to improve their outlook for next season, but that doesn't mean they've been completely inactive. They used some of their international signing bonus pool money and signed two of the best available prospects in brothers Victor Victor Mesa and Victor Mesa Jr. out of Cuba to bolster their farm system. Other than that, it has been all J.T. Realmuto rumors, all of the time.

The club has reportedly been making pretty big asks for the All-Star catcher, seeking Cody Bellinger from the Dodgers, and one rumor had the Yankees potentially sending Miguel Andujar to Miami in a three-way trade involving the Mets' Syndergaard. Bellinger and Andujar are the types of players Miami should be asking for. Last year when the team unloaded Christian Yelich, Marcell Ozuna and Giancarlo Stanton, the club went for a high volume of prospects. While Lewis Brinson didn't have a great year as the centerpiece in the Yelich deal, he has plenty of time to right the ship. For the Marlins to move Realmuto, getting a proven major leaguer with years of control makes a lot of sense, but if they can get a package of players headlined by a top-25 prospect, they shouldn't shy away from it just because Brinson didn't look good last season.