As the saying goes, "Don't give the other team extra outs".
Especially when there are two runners on base, with two outs in the inning, and Josh Hamilton on deck.
Hamilton smoked a three-run home run to deep left center field to give the Texas Rangers a 6-2 lead in the fifth inning, after shortstop Brandon Hicks committed an error on a routine ground ball that could have ended the inning.
That capped off a five run fifth inning for the Rangers, who never looked back, adding an insurance run in the seventh and went on to win 7-2.
The A's had a 2-1 lead going into the fifth inning, after Chris Carter hit his second home run in as many days, and Brandon Inge knocked in a run with a single.
But it was the errors that proved costly - the A's ended up with three on the night.
Martin Perez pitched 5 2/3 innings in his first career major league start, giving up two runs on six hits.
Tommy Milone took the loss for the A's, and he is now 8-6.