In-house upgrades for contenders

Anthony Rendon is ready to help out the Washington Nationals. AP Photo/Kathy Willens

Baseball has now passed the quarter mark of the season, meaning that a player or team's slow start can no longer completely be written off as just another April slump. Most teams haven't thrown in the towel yet -- and teams such as the Houston Astros and Miami Marlins already have traded most of their players with value -- so pulling off a trade deadline-type rental is difficult in May.

As a result, most team upgrades at this point of the year will be made in-house, from players already in the organization. Contenders in particular have good reason to have limited patience with their biggest holes. So, which players likely to be called up will have the biggest potential impact on pennant races?

Note: We're focusing on contenders here, so a player such as Christian Yelich of the Marlins doesn't make this list. For each player listed, the ZiPS Rest-of-Season projection is included.


Anthony Rendon, 3B, Washington Nationals

The Nationals and the prospect-hounds never really had a great deal of concern about how good Rendon would be. The questions around him tended to circulate around his ability to stay on the field because of a history of ankle injuries. Healthy so far in 2013, Rendon has hit .346/.482/.654 for Harrisburg and already has received a taste of the majors when Ryan Zimmerman was injured.