Terry Ryan just made exactly the kind of trade he had to make.

The kind of trade that made him one of baseball's best general managers in the 2000s.

The kind of trade that might not be appreciated for years.

The kind of trade that might doom the 2013 Twins to the sump-pump corner of the AL Central basement.

With the first major trade of his second stint as the Twins' general manager, Ryan did what he was obligated to do. He dealt his most tradable asset for exactly the kind of player the Twins desperately need.

He traded Denard Span, a valuable player made superfluous by Ben Revere and a farm system loaded with outfield prospects, for Alex Meyer, who throws in the mid-90s and spent last season in Class A.

This deal will anger fans who wanted Ryan to fix the Twins' 2013 rotation. The acquisition of a pitching prospect, and the team's interest in prodigal arm Francisco Liriano, are indications that there will be no quick fixes to the Twins' biggest problem. But then there have been no quick fixes for the Twins since Andy MacPhail tried to sign Kirk Gibson and Mike Boddicker in 1991, missed, and had to settle for Chili Davis and Jack Morris.

Ryan built a winner in the late 1990s and 2000s by stealing excellent or under-appreciated talent from the depths of other teams' farm systems. Even if Meyer turns into an ace, this won't rank as one of those one-sided deals. Span is a valuable leadoff hitter who will help the Nationals at a position of need. The Nationals are so stocked with pitching that they can afford to trade a Meyer.

This is already a good deal for Washington. Ryan needs history to repeat itself for this to become a good deal for the Twins.

Ryan can call his résumé as a character witness. Here are a few of the minor-league prospects Ryan acquired before their names were recognizable outside of family gatherings: Johan Santana, Kyle Lohse, Joe Mays, Jason Bartlett, David Ortiz, Cristian Guzman, Eric Milton, Lew Ford, Joe Nathan, Liriano. Who'd he trade for those players? Chuck Knoblauch after he begged to be traded, A.J. Pierzynski when Joe Mauer was ready to take over as catcher, and nobody else you'd care to remember.

Trading Span for Meyer means the 2013 rotation might look a lot like the 2012 rotation, with the addition of Kyle Gibson. If Ryan can't miraculously find a major-league-ready top-of-the-rotation starter this winter, and the odds are that he won't be able to, the 2013 Twins will be in sad shape, but the 2014 or '15 Twins might have a chance to compete.

If the 6-9 Meyer can join Gibson at the top of future rotations, and if Scott Diamond can be a No. 3 starter, and if the Twins can start developing serviceable arms like they did under Ryan in the 2000s, the franchise might soon be able to pencil in a pitching roster that doesn't read like satire.

Trading Span for pitching was precisely the right idea, and it has been since Revere proved he was a far superior center fielder. Span is the more polished offensive player, but Revere covers far more ground, and the current Twins pitchers need all of the help they can get in Target Field's canyons.

If the Nationals think Span will improve their lineup, they're perceptive. If they think he's a Gold Glove candidate, they need to fire their scouts. Span's best fielding season came in right field at the Metrodome, where he was spectacular.

Manager Ron Gardenhire was wrong to use Span in center field when Revere was available -- unless Gardenhire was trying to market Span to teams looking for a center fielder, in which case the plan worked.

Whether this proves to be a good deal is up to Meyer, but this was the right kind of deal. The most precious commodity in baseball is good, young starting pitching. The Twins traded someone who is replaceable for something that is invaluable. Now, as so often has been the case, Ryan has to wait, and hope he picked the right kid from the litter.

Jim Souhan can be heard Sundays from 10 a.m. to noon and weekdays at 2 p.m. on 1500-AM. His Twitter name is SouhanStrib. jsouhan@startribune.com