On April 21, the Cubs and Nationals were both sitting at .500. Despite their mediocre starts, and despite playing in top-heavy divisions with improved rivals, both teams had decent playoff odds: Per FanGraphs, Chicago was at 51 percent, and Washington was at 74 percent. Exactly four weeks later and after splitting two games between them with a date on Sunday Night Baseball looming, the Cubs are rolling (with their odds clocking in above 80 percent), and the Nats are reeling (at 44 percent). We asked ESPN scribes Jesse Rogers and Eddie Matz to break down the inner workings of the two clubs. They kindly obliged.

CUBS KEEP WINNING SERIES; NATS KEEP LOSING 'EM

ROGERS: The Cubs simply have built a culture in which losing is no longer an option. Now, that doesn't mean they're going to win every game -- see the end of last season -- but it does mean they're more likely than not to get back into a race. From the outside looking in, it doesn't seem that the Nats have that kind of vibe. Anthony Rizzo said it recently: a nice, winning season is good for a team such as the Padres. Not for the Cubs anymore. Where are the Nationals in terms of this raised level of play, for which the floor is a playoff appearance?

MATZ: After a disappointing 2018 season and an even more disappointing start to 2019, Washington's floor has bottomed out like that carnival ride on which you and your buddies all stick to the walls (I believe it's called "The Rotor," if memory serves). Heck, these days, the Nats are thrilled just to win a series, something they did Thursday for the first time in a month. Between besting the Giants back in mid-April and taking two of three from the Mets earlier this week, Washington lost seven straight series, including one to the Marlins (Miami's only series win this season). Through it all, manager Davey Martinez, who apprenticed under one Joseph John Maddon Jr. before taking the helm in D.C. last year, kept saying how proud he was of his players. Imagine how proud he'll be if the Nats can start winning with any kind of consistency.

ROGERS: Well, if it's winning series you're looking for, you've come to the right place. The Cubs just lost their first one in a long time. Before the Reds took two of three earlier this week, Chicago had gone 9-0-1 in its past 10 series. The key to it has been a starting rotation taking over games. That's another perplexing thing about the Nats. On paper, theirs is a great staff -- in the winter, it was probably considered better than the Cubs' -- but it hasn't translated to more wins for you guys. One other thing motivating the Cubs is the division they're in. They know how competitive it's going to be all summer and have made a point of reminding themselves of that often. It's a tough division. Sound familiar?

MATZ: First things first: I do not play for the Nationals (you guys?). But if I did, I'd certainly be second-guessing all the success my team had the past few years. Now that the division is more like the NL Beast than the NL Least, all those wins and playoff appearances seem less a product of "Natitude" and more a function of foes' flatitude. Having said all that, though Scherzer has yet to kick into vintage Mad Max mode, it's hardly his fault that his mates are giving him the deGrom treatment so far this season. I'll still take him, Strasburg and Corbin over any big three in baseball. As for the other 20 or so guys on the roster, it's a little more complicated.

LEADERSHIP, INJURIES AND LIFE AFTER BRYCE HARPER

ROGERS: That's where leadership has to play a role. If your best players are also your best leaders, manager X has it as easy as it comes. When a veteran role guy is your best leader, that can work as well. The scenario that might not work is when your best player is anything BUT a great leader. This is actually why yours truly picked the Nats -- yes, the Nats -- to go to the World Series this year. I was thinking of it this way: Addition by subtraction. I thought -- maybe -- by losing Bryce but maintaining tons of talent, Washington might gel. My thinking was the attention would be off them and Davey, even though they're playing in a tough division. I don't know much about Max Scherzer, but it's hard to lead from the mound. So this is a long way of asking you: Where is the leadership on this team post-Bryce?

MATZ: Leading from the mound is uncommon, but Scherzer's that rare breed who has the résumé, cache and work ethic to pull it off. On the position side, Howie Kendrick definitely fits the vet role player mold. But all that clubhouse stuff doesn't much matter when the on-field product has been so consistently lousy. I too thought the 2019 Nats would benefit from a plus by minus situation in which they didn't have to deal with all the drama that surrounded Harper's tenure in the District, especially in recent years. But the bullpen has been brutal. Juan Soto, whose big bat was supposed to be the insurance policy for life after Bryce, has looked more like Mario Soto at the plate. And losing Trea Turner and Anthony Rendon to injuries has been killer. That said, the Yankees lead MLB in player days lost (more than twice as many as Washington), and they're doing just fine. Know who else has lost more time to injuries than the Nats? I'll give you a hint: It rhymes with Schmicago Schmubs.

ROGERS: Injuries? That's the least of the Cubs' problems even though their closer (Brandon Morrow) and his backup (Pedro Strop) are both out. Over the past few months, the organization has had to navigate more off-the-field issues than most do in a decade. First, the owners had to distance themselves from their father after bigoted emails associated with him emerged. Then recently the Cubs brought back infielder Addison Russell after a 40-game suspension for domestic abuse associated with his ex-wife. He took the place of veteran Ben Zobrist, who left the team as he and his wife have filed for a separation/divorce in two states. All this while Joe Maddon exists as a lame duck manager. I mean, technically, Davey Martinez has more job security than Maddon.

WHAT'S NEXT?

MATZ: The Nationals already fired pitching coach Derek Lilliquist earlier this month. Injuries or no injuries, there are plenty of folks around D.C. who think the manager should be next. Since inheriting a team that averaged 96 wins per season under his predecessor (Dusty Baker), Martinez has guided Washington to a sub-.500 record. With Turner's return in Friday's opener, the Nats are as whole as they've been in a long while. If they can't get hot with him and Rendon in the lineup (and with Scherzer & Co. atop the rotation), then the winds of change might start blowing.

ROGERS: For the Cubs, the converse of firing Martinez would be to extend Maddon's contract, but that probably isn't going to happen until the end of the season. Speaking of extensions, Kris Bryant might deserve one after his performance Friday. He has returned to elite status at the plate after a shoulder injury limited him last year, but his long-term future with the team is anyone's guess. Both he and Javier Baez are going to be due generational money someday, and fans will be wondering if the Cubs can pay both.

But that's for later. For now, it's about grinding out series wins as the schedule moves to the second quarter of the season. The Cubs have positioned themselves nicely after a slow start. Pulling away might be difficult in the NL Central division, but Chicago's play since the first 10 days of the season speaks volumes. The Cubs are to be reckoned with once again this season.