I have no clue, I was just passing along what the Cubs Twitter account said. ArizonaPhil can go argue with the blue check mark. I don't always look for an argument.
Below is Phil's detailed explanation about Medina.
As to Teagarden, he is out of options. So, if unclaimed, will be outrighted--if gives permission for an outright. Will be off 40-man.
Submitted by Arizona Phil
on Sat, 08/01/2015 - 9:04pm Permalink
RHRP Yoervis Medina was Designated for Assignment to make room on the Cubs 25-man roster for Tommy Hunter. (Hunter takes Junior Lake's slot on the 40-man roster).
Optional Assignment Waivers must be secured before Medina can be optioned to the minors, and although Optional Assignment Waivers had been secured in the previous waiver period (and once secured, the waivers were good for the entire waiver period), that waiver period ended yesterday at 4 PM (Eastern), and therefore the waivers have expired. So now the Cubs will need to run Medina through Optional Assignment Waivers in the new waiver period (and that takes two days) before he can be optioned to the minors.
The key to making this procedural move is that because the Cubs MLB Reserve List (40-man roster) was full when Medina was Designated for Assignment, another player cannot replace Medina on the 40-man roster while he is Designated for Assignment (or else he cannot be returned to the 40-man roster and be optioned to the minors). So expect the Cubs to go with a 39-man Reserve List until Optional Assignment Waivers are secured, and then Medina will be returned to the Cubs MLB Reserve List (40-man roster) and can be optioned to Iowa (probably on Monday or Tuesday).
BTW, that is NOT the case with RHRP Ben Rowen, who was Designated for Asignment to make room on the Cubs MLB 40-man roster for Dan Haren. So because Rowen was replaced on the 40-man roster by another player after he was Designated for Assignment, he cannot be optioned to the minors. He must be either sent outright to the minors, traded, or released.