Exactly a month ago, the Cubs offense ranked…

You know what?

We don’t need to go into all that.

Let’s just say the statistics were historically unkind for the Cubs lineup through April 16.

But since then?

It’s a completely different story.

Over the last month (starting with the 13-run outburst against the Braves on April 17), the Cubs offense has been among the best in Major League Baseball in just about every category:

OPS — .776 (1st)
OBP — .340 (2nd)
SLG — .437 (2nd)
Runs — 143 (3rd)
wRC+ — 113 (3rd)
AVG — .259 (5th)
BB% — 9.6 (6th)

That’s a pretty big sample size showing this lineup is exactly what the Cubs hoped it would be entering the season.

So what’s behind the change in fortunes as they’ve averaged 5.5 runs per game over the last month?

Kris Bryant has had an MVP-caliber start to the season and ranks among the league leaders in nearly every offensive metric.

Javy Báez and Joc Pederson have turned things around since a slow start, Jake Marisnick was on a tear before getting hurt and Nico Hoerner has hit well since being recalled from the minor leagues.

But one of the major changes is the regular addition of one player into the lineup: Matthew Michael Duffy.

“He’s been huge,” David Ross said before adding, “I guess that’s an understatement.”

The veteran flew under the radar in spring training and most outside the organization weren’t pegging him for a spot on the Opening Day roster.

But the Cubs have liked his contact-oriented approach for years and believed he fit in well with this lineup that has a tendency to be all or nothing with home runs and strikeouts.

“The front office staff really loved my ability to make adjustments and put the bat on the ball and not try to do too much and keep it simple,” Duffy said. “They thought that fit really well with the guys they had in the clubhouse already.

“It’s huge for me, especially the way the game of baseball has been going over the last 4-5 years. To hear that and have them have that confidence in me, I don’t feel like I have to change and be somebody that I’m not. I can just focus on being the best version of me and they appreciate that. It’s a really good feeling.”

It has been a classic win-win situation.

Duffy has hit .306 with a .392 on-base percentage over the last month. He’s come up with a number of clutch hits in that span, including a 5-RBI game Saturday.

When Bryant was asked recently about Pederson’s recent hot streak and how that boosts the lineup, he brought up Duffy’s impact unprompted.

“Looking forward to that definitely and just mixing in guys with really professional ABs like a Matt Duffy,” Bryant said. “It’s just huge for this team. We all kinda feed off of that and hopefully we can keep doing that.”

Even the pitchers have recognized his impact.

“Having Matt Duffy all around the lineup is huge because I feel that he’s been changing a lot of mentalities on this team with the way that he goes about his day every single day,” Adbert Alzolay said. “I feel that he plays a really important role in our clubhouse — not just for the hitters but for everyone in general.”

[MORE: Matt Duffy came up with a huge assist for Adbert Alzolay in the Cubs dugout]

After starting just 1 of the team’s first 16 games, Duffy has been penciled in for 17 of the Cubs’ last 23 contests.

The Cubs have dealt with a lot of injuries to their position player group during that time, but Duffy has also made his value clear with his on-field performance.

He has started games at third base and left field (after never playing outfield in his big-league career prior to this season) and has hit all over the lineup — first, third, fifth, sixth, seventh.

“I’ve seen the entire group — the contact has just gone through the roof in general since Duff’s been in the lineup and getting those types of hits,” Ross said. “The singles have played a lot more into driving guys in and having success and guys understanding that still with 2 strikes, the ability to put the ball in play. I think that’s contagious.

“Duffy has brought an element to that. I think [Eric Sogard] does a good job of that as well — a contact bat. But definitely [Duffy’s] approach, his professionalism in the box is contagious for our group. No doubt about that.”

Ross is correct: The Cubs’ contact rate has skyrocketed since Duffy entered the lineup on a more regular basis.

Prior to that offensive outburst on April 17, the Cubs were last in baseball with a 70.6 contact percentage. Since then, they rank 10th in MLB with a 76.5% contact rate.

The Cubs have been talking for the last couple years about trying to diversify their lineup as a whole and Duffy’s success has shown why.

His homer Saturday marked his first longball of the year and throughout his career, Duffy has not been much of a power hitter (he has 23 homers in 486 MLB games).

But he’s spent most of his time hitting in the heart of the Cubs order and Ross likes him there for that contact-oriented approach.

They always say hitting is contagious and Duffy has proven why he is the Cubs’ “sparkplug,” as Ross called him.

Twice on Saturday, he got into a 2-strike count but both times, he stepped out of the box, cleared his head and stepped back in to deliver big hits (an RBI double and the homer).

“A couple of the at-bats, [strike 2] happened with a pitch over the middle of the plate that I thought if I was a little more free and easy with my mind and my approach, I should have at least pulled the trigger on,” Duffy said. “That’s when I’ll really take a little bit of extra space between me and the box and focus and just realize that I don’t have to get the perfect pitch.

“Once I get to 2 strikes, I have to really reset my mind and realize that I’m going into battle mode now and just be extremely short to the baseball and not overthink it.”

Over the last month, the Cubs aren’t just beating up on subpar pitching, either.

They forced Clayton Kershaw into the shortest outing of his career and held their own against reigning Cy Young winners Trevor Bauer and Shane Bieber over the last couple weeks.

On Sunday, it was Tigers ace Matthew Boyd who came into the game with a 1.94 ERA and 0.94 WHIP before the Cubs touched him up for 5 runs on 6 hits.

Ross and the Cubs have also been happy with their hitters’ aggressiveness this season. That was a major focal point coming into 2021 — being ready to jump on a pitch at any point in the count.

Bryant has found success early in at-bats this season and Ian Happ has followed suit of late, with a couple of first-pitch hits over his last few starts.

“The decision to be on the attack, to be aggressive — especially against the good pitching that we’ve faced lately — has definitely paid off and been beneficial for us,” Ross said.

The Cubs are seeing positive results with the changes to their lineup-wide offensive approach and seem to have the right mix of contact-centric veterans to augment the All-Star sluggers.

As the weather starts to warm up, this Cubs offense could really put on a show this summer.