"The April 2013 Standard arena rotation is now online. On the first Monday of each month, we will be cycling the Standard arena pool. Rather than only having access to the same standard arenas day in and day out, each month we will now feature 24 arenas selected as playable for Standard-level matches.
Newly released arenas will remain exclusive for at least three months, but every other arena is eligible to be included in the cycle."
Standard Map Pool:
Start date: April 1, 2013
End date: May 6, 2013
Duel
TDM
CTF
Almost Lost
Arena Gate
Battleforged
Camper Crossings
Cold War
Courtyard
Dueling Keeps
Electric Head
Eviscerated
Focal Point
Forgotten
Hektik
House of Decay
Inner Sanctums
Jumpwerkz
Leviathan
Left Behind
Lost World
Overlord
Realm of Steel Rats
Space Camp
Space CTF
Theatre of Pain
The Edge
Links:
Official announcement
No, bloodrun is not in the standard pool this month.