It’s nearly impossible to overstate how impressive May was for the Cubs.

For starters, they accomplished something that had not been done since 1916:

The @Cubs have now played 25 games in a row without losing by multiple runs, the longest streak by an NL team in a season since the 1916 Giants!

The Giants did it in 29 straight (and only lost one game in that span).

— Jeremy Frank (@MLBRandomStats) May 29, 2021

Sunday’s 5-1 loss to the Reds snapped that streak. The Cubs’ first 7 losses of the month all came by just 1 run.

That history-making run illustrates how well the Cubs have been playing for a while. They went an entire month where they either had the lead or the tying run up at the plate at all times. That’s pretty wild.

In total, the Cubs went an NL-best 19-8 with a +46 run differential in May. It’s their most wins in a calendar month since September 2017 (19) and best run differential in a month since May 2018 (also +46). 

With June approaching, let’s take a look back at what we learned about this team in May:

1. This team is a bonafide playoff contender.

While the external expectations may not be very high, the Cubs have always felt internally that they could compete this season. 

They’ll occasionally drop in a phrase like “for us to get to where we want to go,” casually mentioning their playoff aspirations and mapping out their hope for how 2021 will play out. 

After going 11-15 in April, the Cubs needed a big May to keep those October thoughts pertinent and they delivered. It wasn’t just the wins, but who they beat and how they won the games. 

The Cubs began the month by sweeping the defending champion Dodgers at Wrigley Field, claiming both games of a doubleheader against former Cy Young winners Clayton Kershaw and Trevor Bauer. They took 3 of 4 from a Washington Nationals team that won the World Series in 2019 and the Cubs also went into St. Louis and won the series against the first-place Cardinals.

They forged an identity over the month as a team with grit and fight that feels like they’re never out of a game. The offense has come around to be a consistent force, the bullpen was phenomenal and the starting rotation rebounded after a tough April. 

This is still a team with a winning culture, an ultra-competitive manager and a roster packed with players who boast long track records of success and feel like they have something to prove this year.

“I feel like everybody’s pulling on the same end of the rope,” David Ross said. “It does feel like it’s continuing to next man up and we do a nice job going out there competing and trying to win baseball games. You feel that from our dugout — the guys are into every pitch and it’s encouraging. 

“We knew we had a good team to start the season and when you get to prove your beliefs and have a really good month like we had, it’s always encouraging. But we got a long way to go as well.”

2. This is going to be a really interesting summer.

May was great for the Cubs, but like Ross said, the key is carrying that success over to June and July. That will be no easy task when the upcoming schedule is significantly tougher than May’s slate. 

Starting with Monday’s 7-2 win over the Padres, the Cubs are playing 10 straight games against the top teams in the NL, including a 7-game road trip to San Francisco and San Diego. Add in a home series with the Cardinals, a 4-game set with the Dodgers and a 3-game series in Milwaukee and the Cubs are going to find out exactly how they stack up against the rest of the league in June. 

If the Cubs keep winning, they could solidify themselves as buyers at the trade deadline. If they fall off, Jed Hoyer still has a lot of valuable pieces to deal away in exchange for prospects.

Either way, the next couple of months are shaping up to be extremely interesting for both the short-term and long-term future of the Cubs franchise.

“We’re not really paying attention to that right now,” Javy Báez said. “It’s gonna be a long season. … We’ll see. We’ll see how these young guys keep getting adjusted to the team and showing what they can do.”

3. Depth matters and not just for the Cubs.

In April’s iteration of this story, we said the Cubs’ depth was being tested early. We had no idea what was in store for this team in May.

Injuries are up at an alarming rate around the game and the Cubs felt that in a major way. 

Entering June, here’s the list of injured Cubs players:

Anthony Rizzo (back)
Jason Heyward (hamstring)
Nico Hoerner (hamstring)
David Bote (shoulder)
Matt Duffy (low back)
Trevor Williams (appendectomy)
Jake Marisnick (hamstring)
Justin Steele (hamstring)
Alec Mills (low back)
Trevor Megill (forearm)
Austin Romine (wrist)
Rowan Wick (side)
Jonathan Holder (shoulder)

The Cubs hope to get Rizzo, Heyward and Marisnick back in the lineup soon while Megill and Mills might be able to rejoin the pitching staff over the next couple weeks. 

Despite all the injuries, the Cubs have been able to maintain their winning ways. The replacements from the minor leagues have filled in admirably and Monday was another example of that as Patrick Wisdom (2 homers) and Kohl Stewart (0 ER in 5 innings) led the Cubs to victory over the Padres. 

“We noticed in spring training how deep this squad was and how well everyone is able to perform,” Eric Sogard said. “Unfortunately we have had some injuries but you know we have guys stepping up, guys ready who come in and fill the job. That’s why we’re continuing to win even though we don’t have all our bullets. With the depth of this team, we’re able to win more ways than one.”

4. This lineup is a grind. 

No matter who’s in there, this Cubs lineup is exhausting for opposing pitchers to navigate through.

On Sunday, the Cubs got just 1 hit and 1 walk through the first 5 innings but forced Reds starter Tyler Mahle out of the game because he had thrown 98 pitches. 

Monday, they hit 5 homers as a team and chased Padres starter Chris Paddack after 4.1 innings (93 pitches).

It’s the type of grind-it-out approach up and down the lineup they have been searching for since 2016. High-contact bats like Duffy and Hoerner have helped shape the complexion of this offense and they can beat teams in many different ways instead of being so homer reliant.

Once the lineup returns to full health, it looks like a group that should do some major damage this summer. 

5. Kris Bryant’s versatility is paramount to this team’s success.

This relates directly to the two previous points. A gigantic reason for the success of the lineup and the team’s depth is Bryant’s ability to play pretty much anywhere.

Joc Pederson goes down with an injury? Bryant moves to the outfield. Ian Happ misses a week? Sure, Bryant can play center. Rizzo’s back is acting up again? Bryant can move in and play first, too. No problem.

Whatever the Cubs have needed, Bryant has provided and he’s done it all while hitting in the heart of the order and posting MVP-caliber offensive numbers (.324 AVG, 1.017 OPS).

He’ll carry a 13-game hitting streak into June.

6. The rise of young pitching is real.

The position player depth has been important, especially of late. But the most encouraging sign for the future of this franchise has been the ascension of the young arms.

Adbert Alzolay has been a consistent contributor in the rotation and continues to learn valuable lessons every outing. 

Keegan Thompson got off to one of the best starts in Cubs history. He had 15.2 scoreless innings to begin his career before allowing a solo homer to Fernando Tatis Jr. in the 6th inning Monday. That’s the 2nd longest streak in Cubs franchise history behind only Larry Cheney (28 IP) and he’ll enter June with a 0.52 ERA.

Justin Steele emerged as a high-leverage reliever prior to his hamstring injury and has displayed some nasty stuff from the left side.

Tommy Nance isn’t necessarily young (30) but the rookie has been immediately thrust into a setup role and has excelled with a dominant repertoire, including this eye-popping pitch to end Monday’s game:

Oh that's nasty, @TomNance34. pic.twitter.com/DVZqBMYp8l

— Marquee Sports Network (@WatchMarquee) May 31, 2021

The rookies have contributed in a major way to the team’s success in May and part of that can be attributed to how they’ve been welcomed with open arms by the veterans in the locker room.

“We’ve got a lot of guys that mutually respect one another and know their place in a locker room,” Ross said. “Also an understanding of veterans that know they need the young guys to perform for us to get to where we want to go. I think that’s a good thing that we’ve got going on and it’s a good mix that we got.”

7. The Cubs are going to be aggressive with their roster.

The young players have performed admirably but it’s also notable how they’ve been afforded an opportunity. The Cubs have been aggressive in cutting ties with veterans and opening up an avenue to playing time for youngsters.

They designated reliever Brandon Workman for assignment, creating an opportunity for Steele and Thompson. Veteran catcher Tony Wolters also was DFA’d and P.J. Higgins promoted to take his spot. 

Hoyer called this a year of transition before the season as the Cubs assess pieces that could become part of the next championship core. The front office has backed that up by providing those players a real chance to show what they can do.

8. The rotation has rebounded nicely.

After a tough April (29th in ERA), the Cubs starting rotation has righted the ship in May to the tune of a 3.18 ERA in May (5th in MLB).

Most of that stems from the turnaround of veterans Kyle Hendricks and Zach Davies. 

Hendricks went 4-1 with a 2.67 ERA and 1.19 WHIP in 5 May starts and that includes a tough-luck performance against the Pirates on Mother’s Day. 

Davies was 1-0 with a 1.72 ERA in 6 outings.

“The first 3-4 years that I was in the big leagues, April was a tough month for me,” Davies said. “It’s not something that you want to continue but you’ve been there before. You know that it turns around. You focus harder with mechanics and pitch execution and it will come. I know from experience that it’s been a slow start for me in years past and that helps.”

9. This bullpen is legit.

May was a history-making month for the Cubs as a team but it also featured the best stretch ever by the bullpen.

Rex Brothers was charged with a run on Saturday, snapping a streak of 38.1 relief innings without allowing an earned run. It was a franchise record and also the 5th best mark by any team since division play began in 1969.

Craig Kimbrel continues to dominate, Andrew Chafin has been as steady as they come, Ryan Tepera turned in a near-perfect month of May and Dan Winkler did not allow a run in 10 outings. Brothers and Dillon Maples have also been solid this season, though they mostly work in low-leverage situations.

Add in Steele (when healthy), Nance and Thompson and it’s a long list of trustworthy options for Ross to turn to.

In May, the Cubs bullpen led baseball with a 1.59 ERA and 31.4% strikeout rate.

10. The fans are making an impact.

As the month wrapped up, Wrigley Field expanded to 60% capacity — which comes out to just shy of 25,000 fans. 

When the Cubs are launching balls into the bleachers like they did on Monday, it sure feels like a lot more than that. Especially when they’re chanting for curtain calls. 

The fans’ energy has been refreshing and provides a legitimate boost to the Cubs roster.

“The greatest thing about this game is the fans and the energy and the moments they’re standing on their feet and you’re having the at-bats,” Ross said. “[Big at-bats] get the fans on their feet and help win ballgames and help give you the homefield advantage and help make you a real big leaguer. 

“When you have a big market team like we have here with the type of fanbase that we have on a sold-out day on a day game at Wrigley and they get on their feet late in the game, that puts a lot of pressure on the other team. The more we’re in that environment, the more it prepares us for the playoffs.”