On Friday, the Houston Astros will take the field wearing a throwback version of their (in)famous 1970s "tequila sunrise" uniform. This will be the third different retro design the Astros have worn so far this season. They previously wore Colt .45s and shooting star throwbacks, with more to come, all as part of the team's 50th-anniversary celebration.
The Astros aren't the only club that's been bitten by the throwback bug this season. All across MLB, teams are turning back the clock, making this the throwbackiest, retro-est, back to basics-est year in memory -- and the season is only one-third over.
Here's a breakdown of teams besides the Astros that have been going retro, and what they've been wearing:
Blue Jays: Technically speaking, the Jays aren't wearing throwbacks this year. But their new uniforms are basically an updated version of their classic 1990s look. It's MLB's most successful new design of the year (even if it's based on an old design), and it's instantly transformed the Jays from one of the game's worst-dressed teams to one of the best.
Brewers: The Brew Crew started wearing their 1980s "ball in glove" era throwbacks a few years ago, and they're continuing to do so this season for the last Friday home game of each month. They'll also be wearing Negro Leagues throwbacks on July 28.
Cubs: The Cubbies haven't yet hopped aboard the throwback bandwagon this season, but that will change Saturday, when they wear 1912 throwbacks for a game against the Giants.
Dodgers: Every MLB player wears No. 42 on Jackie Robinson Day, but the Dodgers took the tribute a step further by wearing Brooklyn Dodgers caps and helmets.
Giants: San Francisco has added an alternate road jersey that harkens back to the Will Clark era. This was always Uni Watch's favorite road design for the Giants, so here's hoping they make this the primary road uni next season. In addition, the Giants will be wearing 1912 throwbacks Saturday.
Mariners: The M's dressed up as the old Seattle Rainiers last weekend. Kudos to them for going the extra mile with throwback batting helmets.
Mets: This year's uniforms mark a return to visual form for the Amazin's. For the first time since 1997, black has been banished from the team's color palette -- no black caps, no black socks, no black undersleeves, no black belts, no black drop-shadow on the lettering and numbering. It may not truly be a throwback, but it's certainly old-school.
Nationals: The Nats will be wearing Negro Leagues throwbacks on July 28.
Orioles: The O's aren't wearing throwbacks per se, but the return of the cartoon bird and the white-paneled cap definitely qualifies as one of this season's biggest retro successes.
Padres: What can brown do for you? Plenty, if you're in San Diego. The Pads revived one of their many brown-and-gold looks on May 18, and they have additional throwback games in store later this season. They've also been distributing throwback Padres uniforms to local Little Leaguers.
Pirates: The Bucs played a Negro Leagues throwback game on May 19, dressing up as the Pittsburgh Crawfords.
Red Sox: The BoSox celebrated the 100th anniversary of Fenway Park's opening last month by wearing 1912 throwbacks. A few weeks later they wore 1936 throwbacks, although those admittedly look very similar to their current design. (One difference: No white outline around the cap logo.)
Tigers: Detroit already has an old-school uni, of course, but they looked even more retro on May 19, when they became the Detroit Stars of the Negro Leagues.
Twins: The Twins wore their pinstriped 1960s throwbacks as their primary home uniform for most of last season, as a memorial tribute to Harmon Killebrew. This year they're no longer wearing the throwbacks for every home game, but they're still breaking them out now and then, and it's still a gorgeous look. The Twins will also be wearing Minneapolis Millers throwbacks on June 30 (sorry, no visuals yet).
White Sox: It's been retro time on the South Side for Sunday home games, as the ChiSox have been wearing 1972 throwbacks -- complete with red shoes!
Yankees: You know the throwback phenomenon is serious when the Bronx Bombers get into the act. The Yanks wore their 1912 design as part of the Fenway Park centennial celebration on April 20. It marked only the second time the Yankees have ever worn a throwback. (The other time was in 1996, when they wore New York Black Yankees uniforms for a Negro Leagues throwback game in Detroit.)
Add it up and you have lots of ways for fans to connect with their teams' histories, along with a varied assortment of fun looks on the diamond -- all of which Uni Watch counts as a good thing.
Paul Lukas can't quite wrap his head around the concept of throwback soap. If you liked this column, you'll probably like his daily Uni Watch website, plus you can follow him on Twitter and Facebook. Want to learn about his Uni Watch Membership Program, be added to his mailing list so you'll always know when a new column has been posted, or just ask him a question? Contact him here.