First, the Kansas City Royals threw down the gauntlet. Now, the Houston Astros have responded. Two smaller market clubs are suddenly acting like the New York Yankees and Boston Red Sox.

What is going on here?

On Thursday afternoon, the Astros proved they want to be serious contenders for the American League pennant by acquiring Milwaukee's star center fielder Carlos Gomez and starting pitcher Mike Fiers. This comes on the heels of Houston's trade for Oakland's Scott Kazmir days ago.

Coming into Thursday, Houston had leapfrogged the Los Angeles Angels for first place in the AL West, with a 57-45 record, leading by one game. Adding Gomez will only help their chances of putting some distance between themselves and the Angels, as the 29-year-old has put up a slash line of .262/.328/.423 this season with 8 home runs, 42 runs scored, 43 stolen bases and outstanding defense in center. Those numbers are lower than his career averages, but he is a two time All-Star and Gold Glove winner and should help solidify center field immediately.

Even better for Houston is he is signed through next season, so he is not a rental. So the 'Stros will get at least another full season from him before they part ways.

Gomez has been at the center of controversy over the last 48 hours, although none of it has been his doing. He was supposedly traded to the New York Mets on Wednesday night, but New York reportedly nixed the trade at the last minute after being unhappy with his medicals. Houston took advantage and snapped him up, apparently finding nothing wrong with the right-handed slugger. However, Gomez has missed time this year with a hip problem, so there is a little bit of risk there.

But he should help out a Houston outfield which has been a bit below average offensively this season. Astros center fielders, in particular, have struggled, tied for 17th in weighted on base average (wOBA) at .308, are 18th in weighted runs created (wRC+ of 95), tied for 26th in batting average (.237), 27th in on-base percentage (.291), and 17th in OPS at .710.

Houston also acquired Fiers, a back-of-the-rotation arm that will help the team give their young starters Lance McCullers and Vincent Velasquez some additional rest. Fiers is a 30-year-old veteran who was having a solid season for the Brewers, sitting at 5-9 but with a 3.89 ERA and a 3.79 fielding independent pitching (FIP). He's striking out 9.23 batters per nine innings and walking 3.28 batters per nine, a decent ratio of strikeouts to walks.

It's unknown exactly where Fiers will slide into the rotation, but more than likely Scott Feldman will remain the number-three starter and Collin McHugh will be the number-four man. Perhaps Houston even goes to a six-man rotation occasionally in order to get the young kids more time off.

However, Houston didn't get Gomez and Fiers for free. The Astros had to give up one of their top positional talents in outfielder Brett Phillips, a 21-year-old playing in Double-A with a .321/.372/.463 slash line in 145 plate appearances. He was the team's second overall prospect. Milwaukee also got a powerful, but strikeout-prone young slugger in Domingo Santana, their seventh-best prospect, as well as pitchers Adrian Houser and Josh Hader.

Houston is in win-now mode, a refreshing change after three straight 100-loss seasons and a 90-plus loss season last year. Their World Series-winning odds went from 7.68% to 11.96% with the deal, giving them the third best probability in baseball, per our metrics. They also only trail the Royals now by just 0.04%.

The Royals and Astros, your new AL superpowers.

Yeah, it's still not sinking in.