Jim Souhan
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The Twins wore white-on-white uniforms this weekend, so you couldn’t tell the players without a program. Or the starting pitchers with one.

In their final game at Target Field before September’s roster expansion and pennant sprint, the Twins sent Martin Perez to the mound. He gave up two runs in six innings to earn the victory, as the Twins won 7-4, and he continued a trend that is part good, part lousy and part worrisome:

The Twins’ rotation is becoming homogenous.

All five starters have ERAs between 3.53 and 4.53. And all have reached a point in their season, if not their careers, where their team is happy whenever they deliver a mediocrity-defining-yet-relentlessly-valuable commodity known as the quality start.

The “quality” start was invented by old friend John Lowe in 1985, when he wrote for the Philadelphia Inquirer. Lowe eventually covered the Tigers for the Detroit Free Press and spent countless hours in Tom Kelly’s office, talking about everything from dog racing to slider grips.

Lowe defined a quality start as six innings or more and three earned runs or fewer. Meeting the minimum standard for a quality start would leave a pitcher with a 4.50 ERA, drawing ridicule from dominant old-school pitchers.

I am here to defend Lowe and the statistic. After Perez exceeded the stat’s minimum requirements on Sunday, the Twins are 44-14 when their pitcher delivers a quality start this season and 35-37 when they don’t.

The Twins have a 3½-game lead over Cleveland with 32 games remaining. Their schedule is favorable, and there is little doubt they will continue to produce runs. After months of consternation about the bullpen, manager Rocco Baldelli now has a reasonable number of attractive options from which to choose, and once rosters expand on Sept. 1, he will be able to keep valuable middle-inning relievers like Zack Littell and Devin Smeltzer around.

Thus, the Twins rotation will be the key to winning the division and competing in the playoffs, and the rotation is in a strange state of flux.

Jose Berrios is the ace and owns the best ERA among the starters, at 3.53, but his ERA this month is 8.44. He could be the fulcrum for October glory or the reason the Twins fail to play past September.

Jake Odorizzi pitched like an All-Star early in the season but has an ERA of 5.49 since June 15.

Kyle Gibson, once thought of as a potential ace, has a 4.49 ERA this year and a 4.47 ERA for his career.

Perez has pulled out of his nose-dive and is 9-5 with a 4.53 ERA. His victory on Sunday was his first since July 5. His career ERA is 4.60.

Michael Pineda has solidified the fifth spot — or is it now the second, third or fourth spot? — in the rotation, going 9-5 with a 4.26 ERA. Since June 29, he is 6-2 with a 2.98 ERA.

Earlier this season, Berrios was the obvious ace, Odorizzi was bidding to become co-ace, Gibson was building on a strong 2018 season, and Perez and Pineda felt like temps. Now they’re all becoming performative clones.

Five starting pitchers offering frequent quality starts should enable the Twins to win the division. Five starters incapable of dominating might keep the Twins from winning their first playoff game since 2004, or their first playoff series victory since 2002.

“Everybody on this team brings something special to the team,” Berrios said. “I have to do my part to do what I can to help this team win.”

Across the clubhouse, reliever Sergio Romo was trying to talk Perez into a dinner of “victory tacos.”

“Win, you eat tacos,” Romo said. “Don’t have a good day? Eat tacos. Makes me feel better. The first thing I did when I got to Minnesota was ask, ‘Siri, find me some good tacos.’ ”

Tacos are like quality starts. When they’re great, they’re great, and when they’re not so good they’re usually still good enough.