Can’t say the Dodgers didn’t learn a thing or three during the 2016 season.

No, Clayton Kershaw cannot pitch every every fourth day, let alone every third, despite how the Dodgers used him in the playoffs this fall. He’s the planet’s best, but he’s not quite a machine.

Meanwhile, Scott Kazmir is not a No. 2 starter, despite what the Dodgers were hoping last spring. Not for a team with championship aspirations. Maybe the Dodgers thought if they wished really hard it might come true — after Zack Greinke, one of the best No. 2s in modern history in 2015, signed with Arizona last winter.

The upshot is, ahead of the 2017 season, the club have signed the man who probably was the best available free agent, and they knew where to find him. On their postseason roster.

Rich Hill was one of the most effective pitchers in baseball in 2016, even if he was limited to 20 starts, with the Dodgers and Oakland Athletics, because of minor injuries.

In 110.1 innings the left-hander struck out 129, against 33 walks, and allowed only 110 baserunners for a scintillating “whip” of 1.00.

He was 12-5 with an ERA of 2.12.

Yes, Hill will be 37 on opening day next year, but he is worth the gamble — and the three-year, $48 million contract the Dodgers gave him. Because if they didn’t offer him serious money some other club almost certainly would have.

The Dodgers are thinking of him throwing 120 to 150 innings (he has never thrown 200 in a season), and running out there whoever else is on the active roster to get through the season.

If it goes according to plan, he and Kershaw will give the Dodgers an edge at the top of the rotation on most everyone if/when they reach the playoffs next fall. Their Nos. 3 and 4 throwers, Kenta Maeda and Julio Urias, should be above-average, as well.

And the Dodgers surely remember the six innings of two-hit ball Hill threw at the Chicago Cubs in the National League Championship Series, as they took a 2-1 lead in the best-of-seven series.

Hill has been fighting injuries most of his career, and was out of organized baseball in 2015 when he signed with the Long Island Ducks, an Atlantic League team without a Major League affiliation.

Hill was nearly unhittable that season, mostly in the International League, and Oakland gave him a $6 million deal for 2016, then traded him to the Dodgers in midseason.

The Dodgers hope Hill has a better year after his big contract than Greinke did. The latter signed with the Diamondbacks for six years and $206 million … then had a mediocre season with a bad team.

The best part of this is that the Dodgers realized they were a couple of pitchers short of a quintet, and signing Rich Hill for $48 million and three years was a good start toward fixing that.