Eighteen White Sox questions for 2018: Why is Welington Castillo the right man for the job?

White Sox fans might have their eyes on the future, but the 2018 season has plenty of intrigue all its own. As Opening Day nears, let's take a look at the 18 most pressing questions for the 2018 edition of the South Side baseball team.

Signing a veteran catcher might not have seemed like the most typical offseason move for a rebuilding team not expected to contend this season.

But the White Sox did an awful lot of good for their present and future in inking Welington Castillo to a deal that could keep him on the South Side for the next three seasons — the endpoint there being the time the White Sox hope their rebuilding efforts reach their apex and the team becomes a perennial contender.

Castillo is coming off a career year both offensively and defensively, which obviously gives the White Sox an upgrade at the position. That's not to say the combo of Omar Narvaez and Kevan Smith were bad in 2017. In fact, they were surprisingly good, with White Sox catchers leading the American League with a .279 batting average and a .346 on-base percentage. But Castillo outdid both, individually, slashing .282/.323/.490 with a career-best 20 homers. Plus, he threw out 49 percent of attempted base stealers last season, the best percentage in baseball, showing a big leap in his defense.

It all adds up to the White Sox having a strong catcher in 2018, which of course can't hurt, regardless of expectations. But a veteran backstop has plenty of value for the team's still-developing pitchers, too, and there could be an awful lot of those on the South Side by season's end. Lucas Giolito and Reynaldo Lopez are already in the rotation, with Carson Fulmer expected to join them at the season's beginning. Michael Kopech figures to be up to the big leagues before the end of September, too. Having an experienced game-caller to help shepherd along the staff of the future — while also producing — is a big deal.

And there's the flexibility, which is becoming a hallmark of all Rick Hahn's moves of late. Castillo's deal could keep him in a White Sox uniform through the 2020 season. That would figure to be around the time when the White Sox are starting to compete on a regular basis. If Castillo is still doing good work behind the plate and with the bat, great. He can stick around and be the starting catcher for a contending club. If Zack Collins, who has played just 12 games above the Class A level to this point, is ready to be a big league backstop by then, great. Castillo will have served as an effective bridge and could be a high-quality backup. Or the White Sox could deal him away for another future piece. Flexibility.

So in the end, what matters is that Castillo checks all the boxes for the present and future. Offensive upgrade, defensive upgrade, veteran catcher for a young pitching staff, a bridge to Collins or the veteran catcher of the future. Whatever the end result, 2018 will be the first year of the Castillo experiment. And it could mean the White Sox are entering their first stretch of having a stable, reliable catcher since A.J. Pierzynski left.