Jonathan Singleton received a long-term contract before he made his MLB debut.
Jonathan Singleton received a long-term contract before making his MLB debut. (USATSI)

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The Astros have agreed to a five-year contract extension worth at least $10 million with top prospect Jonathan Singleton, Jon Heyman of has confirmed. The contract includes three club options and can be worth up to $35 million. Jeff Passan of Yahoo! Sports first reported the deal. Singleton will be called up to join the team immediately. Heyman also reports that the three options are for $2.5 million, $5 million and $13 million.

The contract is historic because Singleton has not yet made his major league debut. Houston offered George Springer, one of their other top prospects, a seven-year contract worth $23 million over the winter, before he made his MLB debut. He rejected the offer, however.

Singleton, 22, has hit .267/.397/.544 with 10 doubles, 14 home runs, 42 walks and 52 strikeouts in 54 Triple-A games this season. It seemed like he would have wait until later this month or early next month to be called up, after the Super Two cutoff. The new contract eliminates the need for service time manipulation.

Baseball America ranked Singleton as the 82nd best prospect in baseball before the season, saying he "has middle-of-the-order potential" in their 2014 Prospect Handbook. The Astros acquired the first baseman from the Phillies in the Hunter Pence trade a few years ago.

Houston is 24-34 so far this season, putting them on pace for 67 wins. That would be their most since going 76-86 in 2010.

The Astros open a three-game series with the Angels at home on Tuesday.