In December 2017, the Cubs signed pitcher Tyler Chatwood to a three-year, $38 million contract. Unlike many lucrative free agent deals, it was an investment not in what Chatwood had done up to that point -- while spending much of his career at Coors Field -- but in what he might do in the future.

"He's uber talented, a right-hander moving into his prime who has great makeup, and we think his best days are ahead of him," Cubs president of baseball operations Theo Epstein said at the time.

Now, after two seasons of frustration, that future might have finally arrived. It’s an opportune development for a Cubs team that is down two starters from its 2019 rotation but is off to an 9-2 start, grabbing the lead in what should be a highly competitive National League Central. It’s also opportune for Chatwood, who at age 30 is set to hit the open market again this winter.

Chatwood, lined up to pitch Thursday at Kansas City, already has logged wins over the Brewers and Pirates. He has allowed only one run on six hits in 12 2/3 innings while striking out 19. His game scores rank as his two of his four best out of his entire tenure in Chicago.

Yes, it’s two starts. But that may represent one-sixth of Chatwood’s season, given the shortened schedule. With a meaningful change to his repertoire and some promising numbers underlying his results, this long-awaited Chatwood breakout could be the real deal.

Where has he been?

Chatwood has long intrigued. He was a second-round pick by the Angels in the 2008 Draft, made it to the Majors at 21, and after getting traded to the Rockies, posted a 3.15 ERA over 20 starts as a 23-year-old in ‘13.

But Chatwood missed nearly all of 2014-15 after having Tommy John surgery, and when he returned, he was haunted by Coors Field (6.07 ERA there over ‘16 and ‘17). At that point, his career numbers were hardly impressive, but the Cubs saw a pitcher who needed a change of scenery. More than that, they saw a 28-year-old with stellar velocity, elite spin rates on his fastball and curve, and a proven ability to get ground balls.

It just didn’t work. Chatwood’s already-shaky walk numbers exploded, left-handed batters torched him, and he lost his rotation spot late in the 2018 season. He bounced back last year but remained mostly in the bullpen.

But in 2020, Cole Hamels is gone and José Quintana has been sidelined. The Cubs’ rotation (1.95 ERA) has not missed a beat, in part due to Chatwood.

A newly minted K artist

Chatwood has never been one to miss a ton of bats. His game was getting ground balls, and his strikeout rate never crossed 20% until last year, when he worked mostly as a reliever. And now, there’s this:

Highest strikeout rate, 2020
Minimum two starts

1. Shane Bieber (CLE): 44.3%
2. Trevor Bauer (CIN): 42.6%
3. Sonny Gray (CIN): 41.2%

4) Tyler Chatwood (CHC): 40.4%
5) Tyler Glasnow (TB): 40.0%
6) Max Scherzer (WSH): 39.6%

Opponents have missed on 38.3% of their swings against Chatwood, which is a top-10 whiff rate, and almost double his career mark entering 2020 (19.5%). Chatwood’s 44.4% whiff rate Saturday against the Pirates was the highest in any start in his career, helping him match a personal best with 11 strikeouts.

Left them behind

Chatwood has significant platoon splits throughout his career, and that issue really came to the forefront in the righty’s first two seasons with the Cubs. He faced exactly the same number of right- and left-handed batters over that time (405 apiece), but with radically different results.

Opponents vs. Chatwood, 2018-19
RHB: .163/.325/.257 (.582 OPS)
LHB: .313/.423/.464 (.888 OPS)

Among the 90 pitchers who faced at least 400 left-handed batters in that time, Chatwood allowed the fourth-highest OPS, a result backed up by his expected stats.

Back to 2020. Chatwood is again dominating right-handers. But opponents have stacked their lineups against him -- he has faced lefties in 70% of his plate appearances -- and the tables have turned. Lefties have gone 4-for-30 (.133) against Chatwood with a .412 OPS, 14 strikeouts and a 39.0% whiff rate.

Cut to the chase

So what led to all these missed bats and miffed lefties? One big reason appears to be Chatwood’s cutter.

In 2019, the pitch receded from Chatwood’s arsenal while he toiled in the bullpen. The results were good, but Chatwood says he was “fighting” the pitch. As MLB.com Cubs reporter Jordan Bastian has written, Chatwood knew he needed to get it back to combat the lefties who were picking him apart. He adjusted his grip, and began to see some positive returns, continuing to refine it while waiting for the 2020 season to begin.

Chatwood is throwing the pitch a tick or two harder than he used to (90.5 mph), and with increased horizontal movement (2.6 inches more than MLB average). The pitch slices away from righties and bores in on the hands of lefties. Was it the missing piece?

Chatwood’s cutter usage vs. LHB
2016: 9%
2017: 11%
2018: 19%
2019: 5%
2020: 28% (35% with two strikes)

Opponents are 0-for-12 with nine strikeouts against the cutter, missing on 59% of their swings. Lefties are 0-for-8 with five K’s.

Not only does Chatwood now have a pitch with which to challenge those lefties inside, but the pitch also complements his sinker. Along with increasing his cutter usage in 2020, Chatwood has used that sinker a bit more while drastically reducing his reliance on a four-seamer.

The pitches both start in the middle of the zone. The sinker veers to Chatwood’s arm side, the cutter to his glove slide. It’s clear how that presents a hitter with a problem.

"When you're lane changing, or tunneling, as it's called now," Cubs manager David Ross said after Chatwood’s season debut. "that sinker off that cutter ... you saw those hitters off-balance a lot, not knowing which lane to choose."

Again, this is two starts. Both were at home, and the second came against a Pirates team with a fairly unthreatening offense. There’s no question Chatwood is overperforming to some degree, and his tendency toward excessive walks could resurface, given a strike rate that remains on the low side. Perhaps hitters, given the opportunity, will adjust to the revamped cutter.

But maybe Chatwood really has unlocked something here. Sometimes a tweak or a recommitment to a certain pitch is all it takes. The cutter and two-seamer are working off of each other, and that high-spin curve is still a dangerous third pitch.

If he continues to solidify the cutter as a weapon, especially against lefties, and keeps the K’s coming, Chatwood just might author the late breakout the Cubs had been anticipating all along.