The first wave of prospect call-ups has happened

September 1st marks the first day that teams can expand their major league rosters. Many teams use this as an opportunity to get some of their younger prospects up to the big leagues to give them experience before being installed as MLB regulars.

Yesterday, teams did exactly that and called up some notable prospects. Here are some of the bigger names that have joined the majors.

Javier Baez, Chicago Cubs

Baez has been lost in the shuffle of other big time Cubs prospects like Kris Bryant and Kyle Schwarber. It has been a long 2015 season for Baez, who has suffered personal setbacks (the death of his younger sister) and a broken finger. Baez brings a ton of pop and a quick bat to the table, giving the Cubs yet another option to turn to in September. 2016 appears to be when Baez will play for Chicago on a regular, everyday basis.

Zack Davies, Milwaukee Brewers

Davies was acquired in the deal that sent Gerardo Parra to the Baltimore Orioles. The 22-year-old is scheduled to slot right into the Brewers rotation, which will ultimately be an audition for him to make the team in 2016. In 2015 at Triple-A (for both the Brewers and Orioles), Davies had a 6-8 record with a 3.30 ERA in 128.1 innings.

Miguel Castro, Colorado Rockies

One of the key pieces of the Troy Tulowitzki deal, Castro's role with the Rockies going forward is unclear. He was signed by the Blue Jays in 2012, and made 15 combined starts between three levels in 2014. In 2015, he made five starts with Toronto's Triple-A team before getting traded. With the Rockies Triple-A affiliate, he appeared in 11 games which all game from the bullpen. The Rockies may look to use him in both roles to see which fit him best.

Joey Gallo, Texas Rangers

This isn't Gallo's first rodeo with the big leagues. as he was called up earlier this year and wowed the baseball world with his eye popping power. Overall, he struggled to put together prolonged success, as he struck out 22 times over his final 11 games, and went 6-for-37. Gallo has a ton of pop in his bat, but a 39.5 strikeout rate with Triple-A is a concern going forward.

Rob Refsnyder, New York Yankees

Dubbed by some Yankees fans as the answer to the Stephen Drew problem, Rob Refsnyder is among the new core of Yankees homegrown talent that is ready to crack the big league roster. Refsynder is going to get his chance to displace Drew as the starter, although he lacked power at Triple-A this season. Look for Refsynder and Drew to platoon at first, and if Refsynder can play well enough, he could be pry the job away from Drew as the Yankees try to chase down the Blue Jays in the AL East.