Not to be outdone by the San Francisco Giants, who acquired Carlos Beltran on Wednesday, or the neighboring Philadelphia Eagles, who signed free-agent Nnamdi Asomugha on Friday afternoon, the Philadelphia Phillies have added an All-Star outfielder with an eye on their third World Series appearance in four years. The deal itself was far from a shock. Philadelphia general manager Ruben Amaro Jr. has a history of swinging major deadline deals. He acquired Cliff Lee in 2009 and added Roy Oswalt last summer. Amaro was not going to let the Sunday deadline come and go without making a major addition. The Phillies were not able to replace outfielder Jayson Werth, who signed with the Washington Nationals for a boatload of money this past winter. The Houston Astros proved to be a perfect trading partner. They had a young star in Hunter Pence and no chance of contending in the near future, so they sent an All-Star to Philadelphia for the third time in the last few years. In addition to the Oswalt trade last season, Houston dealt closer Brad Lidge to The City of Brotherly Love before their eventual 2008 World Series-winning season. While the addition of Pence makes Philadelphia an even stronger World Series contender than they were before, the question is at what cost? Pence comes in hitting .308/.356/.471 with 11 home runs and 62 RBI in a weak lineup. He will immediately improve what has been a middling offense, although it has been better since a healthy Chase Utley returned to the lineup. It will be very hard to beat this team in September and October with guys like Roy Halladay, Cliff Lee and Cole Hamels on the mound and Utley, Ryan Howard and Pence at the plate. But what happens two or three years from now? In order to get Pence, Philadelphia sent their top two prospects to Houston, in addition to a third, a player to be named later and an undisclosed amount of cash. The Astros stocked their farm system in a single trade, adding first baseman Jonathan Singleton, 19, and right-hander Jarred Cosart, 21, who immediately become the two most prized members of the organization. Singleton, an eighth-round pick in 2009, was hitting .282 with nine home runs and 47 RBIs at Class-A Clearwater. Cosart, a 38th round pick in 2008, was 9-8 with a 3.92 ERA in 19 starts for Clearwater. Houston also received Josh Zeid, 25, a righty with a 5.65 ERA in 21 games for Double-A Reading. A lot has been made of the fact that the Phillies were able to hold onto outfielder Domonic Brown, but in the wake of the trade there is concern that Singleton and Cosart had the chance to make a much bigger impact down the road. The arrival of Pence also pushes Brown out of the regular lineup, although that will not last for too long with left-hander Raul Ibanez set for free agency this winter. An outfield that consists of Pence, Shane Victorino and Brown is a nice mix of threats and talent. When it comes down to it though, the Phillies almost have to win the World Series this fall or, dare I say worst case, in 2012. Philadelphia has Pence under control for two more seasons and their current cornerstone players -- Halladay, Lee, Utley and Howard -- are not getting any younger. Amaro essentially emptied the cupboard for Pence and he does not have too much time to restock it before the Phillies are going to need some young reinforcements. It may seem premature to predict this, but it is safe to assume that Philadelphia will look for college players early in the First-Year Player Draft next June. Not only did they deal top prospects for Pence, but they went the same rout in order to land Halladay, Oswalt, Lee and Joe Blanton recently. The Phillies may possess the best record in baseball, but they also have the fourth-oldest roster in the game. Grade for Phillies: C+ Houston may have the worst record in all of baseball, but this deal brightens their future and general manager Ed Wade pulled the trigger on it at the perfect time. They got more for Pence now than they would have when he was just a rental option for a contender and they would not have had much of a chance to re-sign him in a few years when he hits the open market anyway. Grade for Astros: A- The Astros could come out of the deadline with high marks across the board if they are also able to deal left-hander Wandy Rodriguez and perhaps Brett Myers and Michael Bourn before the weekend is over.