After yesterday's game Shaun Marcum's ERA stands at 2.22. In 56.2 innings he's struck out 49, walked 16, and given up 5 homers. His GB/FB ratio is 1.22, which is pretty average (although improved from the last two years). Opposing hitters are batting .151/.220/.281 against him, which is a little ridiculous.
The Hardball Times stats show that Marcum's expected ERA based on his line is 3.44.
So how is Marcum beating his expected ERA and can it continue?