The professional "Twins Fan" at the STRIB had this great stat in a story about Joe Nathan today:
"From 2006-09, Nathan picked 36 spring training innings and yielded only six earned runs."
Nathan has given up 8 runs in 7 games this year in spring training with the Texas Rangers. The statistic above was supposed to show that this was unprecedented and was evidence that Nathan might fail as the Ranger's closer.
You will notice however, "Twins Fan" chose four seasons, ending three years ago, for his comparison. I don't know what his spring training numbers were before 2006, but if you include numbers after 2009, in 2011 Nathan had pitched 8.1 innings in spring training and given up 10 runs. That would kind of change the message And that is about what you would expect from a veteran sports writer posing as a fan. The skill in massaging the facts to fit the story narrative are well-honed by experience.
Perhaps more to the point, spring training numbers are irrelevant. Veterans are getting themselves in shape and preparing for the season. While Nathan's age and injuries certainly make him a candidate to fall off a cliff. His spring training performance doesn't mean much of anything.