Jason Berken and Phil Hughes both fired a four-strikeout inning on the same day

Strikeouts are outs. There are three outs in a half-inning. You might think this means three is the oft-matched record for most strikeouts in an inning. But ... baseball is rarely that simple.

Thanks to Official Rule 6.09(b), a batter can run to first after striking out, and if they make it, it's not an out. Therefore, pitchers can theoretically strike out more than three opponents in one inning, though this theoretical possibility has only rarely become a reality.

But it did on Thursday -- twice. Both the Cubs' Jason Berken and the Yankees' Phil Hughes pulled the trick on the same day. It's the first time that's happened since October 4, 2009, when Luke Gregerson of the Padres and Ryan Dempster of the Cubs did it.

So, Berken and Hughes both tied a Major League record today, but they still didn't match the professional record. A handful of Minor League pitchers, most recently Yankees farmhand Mark Montgomery in 2011, have recorded a five-K frame.

-- Dan Wohl / MLB.com