Ah, Alex Burnett, we hardly knew ye:
Since it was a disabled-list move, it's not really clear why the Cubs wouldn't have just recalled Burnett; he was optioned two days ago, but players can be recalled when there's an injury. I presume Burnett will likely clear waivers (as Michael Bowden did) and will be assigned outright to Iowa.
Blake Parker has been in the Cubs system for seven seasons and is currently in his sixth year at Triple-A Iowa. He made seven appearances covering six innings for the 2012 Cubs and posted... not-so-great numbers, a 2.50 (yes, two point five, not a typo) WHIP and 6.00 ERA. He'll turn 28 in a couple of weeks and isn't any sort of long-term bullpen answer. I suppose Theo and Jed are doing one of two things -- either giving him one last shot to see what he can do, or giving him a couple of big-league weeks as a reward for all the service to the organization.
There's been no official announcement from the Cubs yet, but I'm assuming Parker will be available for tonight's game.