This game would have been a difficult Platinum to begin with. However, on March 17, 2010, a year after the game's release, the online servers were shut down. The game includes 3 online trophies, which can no longer be unlocked, resulting in the Platinum being Not Obtainable.

With the servers shut down, the 3 online trophies are now unlockable, making this Platinum Not Obtainable. However, there are still 26 offline trophies you can collect, so if you're interested, read on.

First, to make life easier, you can adjust the sliders so that yours are turned up, while the CPU is down, and select Rookie difficulty.

Then, you can start a Franchise team and work towards unlocking the Streaker trophy for getting 10 game wins, and the Managerial trophy.

After that, start up a Road to the Show and begin by selecting a non-pitcher position. You should still be playing on Rookie mode, but as you get a feel for the game, switch to All Star difficulty. Focus on achieving all the goals and boosting your stats, and aim for the RttS MVP trophy.

Then, start another Road to the Show, this time selecting a pitcher. Again, switch the difficulty back to Rookie, until you've knocked out the majority of the trophies. Once this is done, the rest is mopping up.

Here's a great Trophy Guide by doug-e freh2435:
http://www.playstationtrophies.org/game/mlb-09-the-show/guide/

trophybot has a detailed Trophy Guide, here:
http://ps3trophies.com/forums/showwiki.php?title=PS3-Trophy-Guides:MLB-09-The-Show-Trophy-Guide

Another useful Trophy Guide, this one by dangles:
http://www.playstationtrophies.org/forum/mlb-09-the-show/62923-mlb-09-show-trophy-guide-road-map.html

And a Trophy Guide by shows-over:
http://www.playstationtrophies.org/forum/mlb-09-the-show/12967-mlb-09-show-trophy-guide.html

Lastly, here's a basic Trophy List:
http://www.xtremeps3.com/2009/12/04/mlb-09-the-show-trophies/