There are two key numbers regarding Ervin Santana.

Both are 32.

Santana has averaged 32 starts over his past five seasons.

Santana turns 32 Friday.

The Twins and the righthanded pitcher agreed to a four-year deal worth $55 million on Thursday. His résumé describes a durable starter who has pitched in pennant races and succeeded in the American League.

In the past two seasons, and in four of his last five, he has posted an ERA under 4.00. In the other, 2013, he imploded, allowing 39 home runs in just 178 innings. Even in that year, his worst since 2007, he made 30 starts.

Santana does not instantly make the Twins contenders, but if he has another 200 innings or so left in his well-used arm, he can help them on the road to recovery.

Free agency does not win championships. That was proved against last season, when the Giants beat the Royals in the World Series. Both teams were mostly home-grown. Both teams had made productive trades. Both teams looked at free agency as mortar, not brick.

The Twins, in need of both building blocks and caulk, theoretically made themselves better Thursday, but there are two points of caution that should be noted:

• Free agent signings, baseball's version of retail therapy, rarely look as good in summer as they do in winter. Last winter, the Twins signed Ricky Nolasco to a club-record contract for a free agent, and, either because of injuries or a difficulty in adapting to the American League, he became one of their worst players.

• If offseason moves were a proper barometer of a team's progress, the Twins still would be trailing most of the American League Central.

The White Sox, in particular, have added Jeff Samardzija, Adam LaRoche, David Robertson and Zach Duke.

The Royals have lost Billy Butler but signed Kendrys Morales, while promising their fans that this Kendrys Morales is in no way related to the guy who played for the Twins last year.

Last winter, the Twins set a team record for free agent expenditures, signing Nolasco and Phil Hughes. Hughes far outpaced expectations. Nolasco flopped. The Twins stunk.

Assuming good health, Santana gives the Twins a chance to field a professional rotation while their best young players develop. That might be as important emotionally as it is numerically.

For four seasons, the Twins have played meaningless games in a lifeless ballpark after emerging from a quiet and sometimes selfish clubhouse.

The team's personality improved some last year. Hughes is a popular figure. Danny Santana is as professional as he is talented. Brian Dozier, Glen Perkins and Kurt Suzuki are veteran pros and competitors.

After a season in which Ron Gardenhire seemed to care more about perception than reality, Paul Molitor will bring a competitive edge to the dugout.

All of which will matter only if the starting pitching improves enough to make games meaningful in August, much less September.

If the rotation fails, the Twins' top prospects — here and en route — will again be playing in meaningless blowouts, and the organization will again be at the mercy of minor league pitching depth.

With Santana under contract, the Twins can at least dream this dream:

Santana provides 200 innings and a sub-4 ERA. Hughes reprises his 2014 season, or comes close. Nolasco arrives in spring training dedicated and determined to making up for his horrific Twins debut.

Kyle Gibson takes another half-step forward — last year he was a poor man's Santana, making 31 starts with an ERA of 4.57. Alex Meyer starts the year in the big-league rotation and starts working his way toward the top of it.

Here's Part 2 of the dream:

By late summer, top prospects Byron Buxton and Miguel Sano will make their major league debuts for a team that is in contention.

The wonderful thing about that dream is it soaked in preservatives.

If it doesn't come true this summer, the Twins will have the same dream, involving most of the same players, again next winter.

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