Tigers prospect Nick Castellanos, who was the 44th overall pick in the 2010 draft, is hitting .302 with 28 doubles and 60 RBIs at West Michigan this season.

The Tigers made their move to bolster their chances at making the postseason with the acquisition of pitchers Doug Fister and Dave Pauley from Seattle.

With the trade they lost four players, including Double-A third baseman Francisco Martinez, one of two Tigers players that participated in this year’s Futures Games during All-Star weekend in July.

That puts the future focus for the Tigers on 19-year old third baseman Nick Castellanos, rated Detroit’s No. 2 prospect by Baseball America. He is now the heir apparent to take over at third base for Detroit in a couple of seasons. There were questions what the Tigers would do in a few years when both Castellanos and Martinez would be ready for the bigs and if one of the highly touted prospects would be in line for a position switch in order for Detroit to get both of their bats in the lineup. That point becomes now moot with the departure of Martinez.

It still bears watching to see how each of the players performs in the future to see which of the players performs better down the line and if the Tigers made the right decision to keep Castellanos over Martinez.

What’s clear is that the future is bright for Castellanos, who was Detroit’s top selection in the 2010 draft and received a $3 million signing bonus.

Since a rocky first month of the season in which he hit just .194, the Davie, Fla., native has been one of the best offensive players in the Midwest League. Castellanos has anchored the cleanup spot for Low Single-A West Michigan and is batting .302 with 28 doubles, six home runs and 60 RBIs as the season winds down.

He has hit better than .300 in every month since the slow April, including a sizzling month of June in which he hit .375. He is hitting .321 since the Midwest League’s All-Star game.

Defensively, Castellanos is still a work in progress and will continue to get better as he gets more experience playing at third base. Castellanos, who has 20 errors this season – including three in an extra-inning loss last month –  played mostly shortstop prior to this season. He has a strong arm so its only a matter of getting more experience at third and boosting his .904 fielding percentage.

Meanwhile Martinez, who is 20,  was hitting .282 with 14 doubles and seven homers at Double-A Erie and has a .909 fielding percentage. He likely will be ready for a full-time job in the big leagues in 2013. It bears watching which one has the better career in the majors and if the Tigers parted with the right third baseman.