The defending World Series champions, the LA Dodgers, were very active as they aim to reel in the surprisingly formidable San Francisco Giants in the National League West. The Dodgers managed to bring in three-time Cy Young Award-winning pitcher Max Scherzer to add to their already impressive starting rotation.
LA also added Danny Duffy to their pitching staff, as well as shortstop Trea Turner. Of course, to bring in these players, they let go of a series of minor league prospects, including their top two ranked players.
Not to be left out, San Francisco added another powerful bat as they took Kris Bryant from the Chicago Cubs in what could be another big win as they pursue a fourth World Series in 11 years.
The Boston Red Sox and Tampa Bay Rays made moves as the two fight it out for the American League East title.
The Red Sox added power-hitting left fielder Kyle Schwarber and increased the depth in their bullpen, acquiring Hansel Robles from the LA Angels.
The Rays had been using players in rotation to fill the Designated Hitter spot, but their trade for Nelson Cruz from Minnesota means they now have someone to plug that hole.
Watching the Rays and Red Sox, the New York Yankees know their best chance of making the postseason is now through the Wild Card but the race for the elusive last spot in the play-offs is now hotter than ever, with Oakland, Seattle and Toronto all within a few games.
The Yankees management has faced more than its fair share of criticism from fans in the past few months and, with their jobs on the line, general manager Brian Cashman and manager Aaron Boone made some moves that could save them.
The Bronx Bombers have not been hitting with their usual level of power this season, with what seemed like a loaded line-up.
They haven't finished outside the top five in home runs scored since the 2016 season but sit in the bottom half so far this year.
The whole baseball world was aware that they needed an explosive left-handed bat with the famous short right porch in Yankee Stadium.
However, Cashman and Boone managed to bring in not one, but two, left-handers with significant league experience.
Joey Gallo arrived from the Texas Rangers for several prospects and Anthony Rizzo was acquired from the Chicago Cubs.
Rizzo immediately ingratiated himself to the Yankees faithful with a big bomb in his first game at the Marlins on Friday.
But of course, every trade is a gamble. If the Yankees make the play-offs, it'll have been worth it, but if they don't, then both Cashman and Boone will be looking for new jobs.
The two trades cost the Yankees their seventh, eighth, 11th, 18th, 22nd and 25th-ranked prospects in their minor-league farm system yet, while this may seem a big deal, Boone and Cashman managed to retained the top talents. So, should both be removed from the jobs at the end of the season, they should at least be credited for is not throwing away the future on one last ride.