Today's September Call-Ups

The first day of September tends to be a pretty big deal for young players around the league. It's the first day that rosters expand, and teams are able to call up any players that are already on the 40-man roster. These players can't play in the postseason given that eligible players must be on the roster by August 31, but it's usually a good time for teams to see what they have in young players that could potentially be key contributors the following season. Let's take a look at the notable call-ups that we've seen so far today:

• The Reds officially called up catcher Devin Mesoraco today. Mesoraco, 23, was rated by ESPN's Keith Law as the sixth-best prospect in all of baseball back in July, and he's done little to dispel that notion since then. Over 120 games with Triple-A Louisville, the former first-round pick has posted a .289/.371/.484 line while showing improved catching skills. He won't be a great defender behind the plate, but his offense could make him one of the best players in baseball.
  
• Cleveland promoted two pitching prospects today in Corey Kluber and Nick Hagadone. Kluber, 25, was acquired from San Diego in last year's Ryan Ludwick-Jake Westbrook trade, and spent all of this season in Triple-A. You wouldn't have expected Kluber to get a call based on his performance, though, as he's posted a 5.65 ERA in 146 innings. Hagadone has pitched much better, posting a 2.79 ERA in 71 innings split between Double-A and Triple-A. This month could end up being the beginning of a long run of success in the bullpen for the former Red Sox farmhand.