The first meaningful September game at Target Field since 2010 felt like the beginning of the last episode of a favorite serial TV show. You don't know how it's going to end or whether it will be renewed.

Tuesday night, players wore presumptuous T-shirts welcoming the next month or two of baseball. September call-ups flooded the clubhouse, turning an often quiet space into what felt like a high school reunion. Paul Molitor and Terry Ryan answered questions about top pitching prospect Jose Berrios staying in Rochester instead of joining the big-league team.

Then, Tyler Duffey — called up instead of Berrios a month ago — looked like one of the Twins' most important players for this September, and perhaps many in the future, for exactly 4⅔ innings.

While the Twins' lineup continued its continuing mastery of the otherwise exceptional Chris Sale, Duffey teased and taunted the White Sox with a customizable curve and seemingly calmed nerves.

Through those 4⅔ innings, ­Duffey looked like the ideal addition to a pitching staff – a pitcher with savvy and underrated stuff.

Duffey not only got the call-up that might have gone to Berrios; he is well past the first-start nerves that Berrios would be subject to if he arrived this month.

On Aug. 5 in Toronto, Duffey faced baseball's most fearsome lineup and allowed six runs in two innings, earning a loss.

Since then, Duffey has gone from a necessary call-up to a key figure in the Twins' playoff chase.

His performance Tuesday made a case for why Berrios should be called up, and why that might not work out too well.

Duffey is 24. He pitched at a major college — well, Rice — before the Twins drafted him. If he's going to be a good major league pitcher, he would probably start showing signs that he is ready at about this juncture of his career. Despite quality experience and an advanced age for a prospect, he got whacked in his big-league debut, and invited the White Sox back into the competition Tuesday after being staked to a 4-0 lead.

Duffey got the first two outs in the fifth inning, seemingly preserving that 4-0 lead. The next five batters reached base, three runs scored, and Neal Cotts was called in. One line drive at centerfielder Byron Buxton ended the inning.

There is no question Berrios is the Twins' best big-league-ready pitching prospect. He is 21. He has pitched in 70 innings above Class AA. He has averaged 9.9 strikeouts per game at Class AAA Rochester. His ERA is 2.67.

Is he ready to pitch in a playoff race?

The only honest answer is "maybe.''

Should he be given a chance?

Since Duffey's debut, he has pitched well enough to stay in the rotation, despite his fifth-inning letdown on Tuesday. Tommy Milone is 6-4 with a 3.86 ERA. Kyle Gibson is 9-9 with a 3.82 ERA. Ervin Santana is coming off an excellent start. Mike Pelfrey has been unreliable of late, but Phil Hughes is coming off the disabled list soon.

There is no guarantee that Berrios will pitch better in his big league debut than did Duffey. If Berrios didn't replace Duffey in the rotation, he would have to replace a veteran big league pitcher.

Berrios is close to his perceived innings limit on the season, even though Ryan wouldn't specify what that limit is. He may be able to make only one or two starts before being shut down for the season.

Should the Twins call him up? The best answer is a question.

Why not?

Why not call up Berrios, let him get used to the big leagues, get used to the pressure of a playoff race, and prepare himself to pitch should the need arise.

Call him up, and let him prepare to start. The move would force the Twins to cut a player off their 40-man roster. That kind of problem is the side effect of contention, difficult but welcome.

Calling up your best pitching prospect in a playoff race couldn't hurt, and it just might help, whether in two weeks or seven months.

Jim Souhan's podcast can be heard at MalePatternPodcasts.com. On Twitter: @SouhanStrib. jsouhan@startribune.com