The Twins opened the 2012 season with Jamey Carroll at shortstop. He was in the lineup for 27 games and the Twins were 7-20, giving early proof that the club’s fall off the cliff a year earlier was not a fluke.

Brian Dozier was called up from Class AAA to take over at shortstop on May 7. He started 82 of the next 87 games at shortstop and was batting .234 with a distressing .271 on-base percentage.

The Twins sent Dozier back to Rochester on Aug. 12. They used the weak-hitting Pedro Florimon at shortstop for most of what remained of a lost season. Second base also had been a mess, with Alexi Casilla starting the season there, and then Carroll playing frequently after he was moved off shortstop.

The Twins went to 2013 spring training without a starting second baseman. They gave a shot to Dozier and it was clear immediately that this was his position, not shortstop.

The averages were in the .240s, but Dozier hit 41 home runs and drove in 137 runs over the next two seasons.

Dozier was not yet arbitration eligible in the spring of 2015 when General Manager Terry Ryan signed him to a four-year, $20 million contract. Even though the Twins didn’t buy up any of Dozier’s free agency time, this contract has proved to be a tremendous bargain.

Dozier is the best second baseman the Twins have had in the two decades since Chuck Knoblauch was traded to the Yankees. Luis Castillo was helpful for sure during his two-year stay from 2005 to 2007, but his legs were aching and he didn’t have much fielding range.

Dozier does everything well in the field, including turn the double play. He can run. He has outstanding power. He’s a complete player. This is the second straight season that he’s the best player on the club, and possibly the third in a row.

Miguel Sano was voted the team MVP in 2015 with big power numbers in half of a rookie season. Dozier’s low batting average, .236, caused him to be dismissed, but add excellent fielding to 28 home runs and 77 RBI, and the first installment on the $20 million contract was well-earned.

Then came 2016. Dozier endured several weeks of derision as he struggled at the plate, and then he became a power-hitting phenomenon. He hit 42 home runs with 99 RBI, huge even for a modern-day second baseman.

A popular refrain from Twins’ skeptics during the offseason was, “No way Dozier is going to hit 42 again.’’

No kidding. It was career power year for Dozier. A player is entitled to have one of those at age 29.

The fact he’s likely to wind up around 30 home runs rather than 40 doesn’t change the fact Dozier is two-thirds of the way through another outstanding season.

He had a series of games a couple of weeks ago so exceptional in the field that he was placed in nomination for a Gold Glove on Twitter (by me). And, yes, the danger in his bat is still there.

On Tuesday night, Adalberto Mejia offered another slow-moving, unimpressive start, before leaving with no outs in the fourth. By the time the half-inning was over, the Twins trailed Milwaukee 4-2.

Matt Garza was Milwaukee’s starter. He didn’t exactly seize this opportunity to beat his original club.

Eddie Rosario hit a one-out home run in the bottom of the fourth. He would hit another in the fifth. Max Kepler had one in the third, and then another in the fourth.

Four home runs from the corner outfielders, and those weren’t the game-changers.

Rosario’s home run in the fourth was followed by a single and two walks. Dozier had a rare chance with the bases loaded as the leadoff hitter.

“I knew he wasn’t going to challenge me inside,’’ Dozier said. “I moved up on the plate. He’s a good pitcher, but he left a fastball up. It’s probably not the pitch he wanted to throw there.’’

First pitch. Fastball. Dozier is always ready to hit that, usually when it’s in, but this time when it was away. He hit a line drive into the right-field seats for his first big-league slam, sending the Twins to an 11-4 victory.

That put his total at 21 home runs, now with 61 RBI. Throw in the way Dozier plays second base, and that’s plenty good … especially at the bargain price of $20 million for four years.