"He's been dealing with some foot issues for a while," Porter said. "It was one of those things where he continued to try to push through it and try to push through it, but it started to affect his shoulder. We just got to the point where, after the doctors looked at it, the problems were getting worse."
As Zeid goes to the DL, Collin McHugh will come off it to start for the Astros on Sunday. Brad Peacock has also been optioned to Triple-A Oklahoma City, with Houston set to announce a corresponding roster move Sunday.
The moves will allow Brett Oberholtzer, who has bounced from Oklahoma City to Houston frequently, to start for the Astros against the A's on Monday.
"Oberholtzer has pitched extremely well, and he earned the opportunity to continue to stay in the rotation," Porter said. "You look at the struggles in which Peacock has had, I think it all starts with his fastball command."