Both the eye test and the number projections show just how good of a move signing starting pitcher Yu Darvish can be for the Chicago Cubs.

Looking around Twitter, a lot of Chicago Cubs fans are still pinching themselves: “Did we really just get Yu Darvish?”

Yes, you did. Bask in the glow for a bit, especially given how this move could help the Cubs reach another World Series.

The Cubs bided their time in a slow free agent market and nabbed Darvish on a six-year, $126-150 million (if escalators are reached) deal, by far their biggest move of the winter.

And in doing so, they create an intriguing foursome of Jon Lester, Jose Quintana, Kyle Hendricks and Darvish come playoff time.

But for a look at just how much Darvish brings to the Chicago Cubs’ starting rotation, let’s look both at what the rotation was projected at this season and where the Cubs would’ve been if they re-signed Jake Arrieta, the other man they were heavily seeking, instead.

Early this week, Baseball Prospectus’ PECOTA rankings, which projects player performance from year to year, cast the Cubs’ hitting in a much more favorable light than their pitching, which makes some sense.

After all, the Chicago Cubs still have several stars, like Kris Bryant and Anthony Rizzo, squarely in or about to enter to the primes of their careers.

The starting rotation, though, looked quite a bit rougher before Darvish inked his deal.

Sliding Mike Montgomery into the rotation by default, this is how projections looked earlier in the week, as provided by Bleacher Nation:

Jon Lester: 28 starts, 196 IP

Jose Quintana: 29 starts, 174 IP

Kyle Hendricks: 29 starts, 165 IP

Tyler Chatwood: 24 starts, 137 IP

Mike Montgomery: 26 starts, 148 IP

That’s not great.

But slide Darvish into the mix, re-run things and the entire outlook changes.

Jon Lester: 29 starts, 183 IP, 2.5 wins above replacement player (WARP)

Jose Quintana: 29 starts, 174 IP, 3.1 WARP

Kyle Hendricks: 28 starts, 160 IP, 2.4 WARP

Yu Darvish: 30 starts, 180 IP, 2.7 WARP

Tyler Chatwood: 24 starts, 127 IP, 0.4 WARP

That allows the Cubs to retain their flexibility and use either Chatwood or Montgomery to strengthen a bullpen that PECOTA really doesn’t like overall. Obviously, these are just projections that players can outperform, but right now, everything’s a forecast anyway.

And, if you do a little bit of comparison between the projections for Darvish and Arrieta, it’s somewhat hard not to feel like Darvish gives the Chicago Cubs more for a whole lot less.

Though Arrieta’s penchant for brilliance shows itself in a lower projected ERA and WHIP, Darvish is projected to throw over 30 more innings in 2018. That’s a big deal, especially in terms of saving the Cubs bullpen.

Interestingly, their WARP numbers are almost identical (2.7 for Darvish vs. 2.6 for Arrieta), so one could view that as a push. That said, getting more innings of good pitching from Darvish wins out from a value standpoint.

And as Darvish gets further from his 2014-2015 elbow issues, a return to his prior form looks hopeful. And 2012-2014 Yu Darvish was better than Arrieta at any point other than the latter’s CY Young season in 2015.

Not to mention that the Cubs got Darvish at a relative bargain (~$21 million per year). Meanwhile, Scott Boras is trying to get Arrieta a $200 million deal probably worth at least $35 million (assuming about a five-year contract).

Of course, the whole season remains ahead for Darvish and the Chicago Cubs. Sometimes, the best-laid plans find a way to go astray. But for now, adding Darvish looks like it has the Cubs in good shape to compete for another title.