Twenty-two months ago the Chicago White Sox finished 41-121, the worst record any team has posted in the modern era. This morning they woke up in first place in the American League Central, three games clear of Minnesota and Cleveland, and announced they had traded for a starting pitcher. Not a rental arm on a cheap expiring deal. Luis Castillo, with two-plus years and roughly thirty million dollars left on his contract, all of it absorbed.

The number attached to Castillo is unflattering and everyone can see it. He is 3-9 with a 5.06 ERA and a 4.57 FIP, the worst full season of a ten-year career that includes three All-Star selections. His strikeout rate has collapsed to 19.4%. Seattle, sitting at 54-58, decided that was somebody else's problem.

So read what Chicago actually bought, because it isn't stuff. Castillo has made thirty or more starts in three consecutive seasons. He is the only pitcher on the White Sox staff who has thrown a pitch in a postseason game. A front office that has spent two years accumulating young arms just paid full retail for the one thing young arms cannot manufacture: innings, and a person who has been there in October. The price was their Opening Day closer — Seranthony Domínguez had already lost the ninth inning to a 14.2% walk rate — a catching prospect, and an outfielder who has not appeared in a major-league game all year.

The club underneath the move is genuinely different, and not only in the standings. By Outs Above Average the White Sox now field a top-ten defense (+10) — a team that two summers ago could not catch the ball is converting batted balls at an above-average clip. Tampa Bay, 65-45 and the better team on paper this afternoon, is the sterner test of whether any of it travels.