Strike Em Out, Throw Em Out
Turn a double play by striking out the batter and throwing out the runner stealing (not achievable in RTTS; only earned if playing an uninterrupted game against the CPU, without switching sides or fast forwarding).

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This will require you to play on anything except beginner pitching difficulty level. To get this the quickest way possible, edit your CPU's roster attributes and increase BR Aggressiveness to 99, lower BR ability to 0 and increase Speed to 60. When in the game, adjust the Baserunner Steal Frequency slider to max. You will also want to have your catcher have max arm strength, Arm Accuracy, Reaction and Fielding Ability.

Start the game as the home team so the CPU bats first. Since you can't fast forward or skip gameplay, this will allow you to attempt the trophy in the first inning and if you don't get it, just hit quit > restart.

Start the inning by intentionally walking the lead-off hitter. The chances are extremely great that the runner on first will attempt a stolen base during the next batter, or the following. You just need to hope he does it on a two strike pitch that the batter swings and misses on. Throw fastballs to reduce the time it takes for the ball to reach the catcher.

Also, decrease the CPU's hitting sliders as such:

CPU Contact
CPU Power
CPU Timing
CPU Foul Frequency
CPU Solid Hits
Immikeulate mentions the following. PS3 method does not work on the Vita. For some reason the Vita version combines BR ability and BR aggressiveness so you need them both at 99. Secondly 60 speed is to low for them to steal, it seems the speed needs to be at least 80. I noticed at 80 they got aggressive on the base paths.