Roster expansion in September can be an exciting time. Stars can emerge from places no one expected, helping to lead a team to the postseason or, with a little luck, a World Series title.
So far, which is admittedly a small sample size of three days, the top contenders in each league haven't made a big splash with their call-ups. Some notable names and high draftees are being brought up, but their impact depends on how much playing time managers give them.
Since managers have spent six months building trust with their 25-man rosters, it can be difficult for these new players to get a fair shake. It can happen, as it did when the Angels used Francisco Rodriguez in 2002.
To keep you up to date on the latest call-ups, as well as which of those players are going to make an impact, here is everything you need to know about the moves the top contenders have made in the American and National Leagues.
Note: Call-ups courtesy of each team's official website.