Ivan Nova is sneakily special.

Six pitchers threw more than 160 innings in 2016, 2017 and 2018, and had ERAs below 4.20 each of those years: Max Scherzer, Justin Verlander, Corey Kluber, Jake Arrieta and Jose Quintana are five. Nova is the sixth.

He is still putting together good outings in 2019, now with the Chicago White Sox after those three years in Pittsburgh. If Mother Nature had not intervened Monday, Nova — who had thrown only 59 pitches with one run allowed over five innings — would have likely had his sixth quality start, putting him in rare company with only 23 other pitchers as of Monday’s games.

But sprinkled among the quality starts have been some absolute stinkers. Eight earned runs in three innings on May 17 against Toronto. Four homers and nine runs on April 23 against the lowly Orioles. He followed up seven innings of one-run ball against Cleveland in his first start of 2019 with his worst ERA start of the year: seven runs in 2 1/3 innings against Seattle.

It all adds up to an unsightly 6.52 ERA, which is belied by an xFIP nearly two runs lower.

So what is contributing to the hot and cold nature of Nova’s 2019? He has always had good control, with a top-ten BB% in 2018, but it’s well above his past few years so far in 2019. He has always been highly BABIP-dependent, with a career K/9 rate of just 6.57. That rate is even lower this year, by nearly a full percentage point at 5.61, and in the lowest 6th percentile of all of MLB. His BABIP is doing him no favors this year at .370, more than 60 points higher than his career average.

Nova’s use of his four-seam fastball went from 31.5 percent in 2018 to less than half that at 14.6 percent. Some of that can be attributed to those pitches getting blasted against Nova this year. On the 133 four-seamers he has thrown this year, hitters have a BA of .517 and SLG of .897. This year he reintroduced a cutter — a pitch he hadn’t thrown since undergoing Tommy John in 2014. He now throws it about 14 percent of the time, making up most of that difference. The pitch has gotten much better results than the four-seamer, producing a .231/.462 AVG/SLG.

Nova’s fastball is down a tick at 92.3 MPH from 93.3 in 2016, and at the age of 32 he will need to continue to come up with new solutions like the return of the cutter to have success.

He is on the last year of a three-year deal and, with the White Sox out of contention, he might not be a bad trade target for a team short on pitching. He has the track record and, some bad starts aside, has shown he can still succeed in 2019.