Porter said he started to feel the effects after Saturday's win against the Rangers in Arlington, but the scratchy throat and clogged sinuses didn't truly become a problem until Monday.
"My throat felt like it was on fire, so I couldn't even cough or hack up because it hurt so much," Porter said. "I couldn't have coached if we had a game on Monday. I couldn't even make it out of bed."
The bug, which Porter claims started amongst the training staff reached the players this week, too. Reliever Chad Qualls couldn't pitch in the first two games against the Royals as he dealt with the sickness.
Starter Dallas Keuchel came down with it, too, but he managed to make his scheduled start Wednesday, going six innings and allowing two runs while leaving the game with a lead.
"That's why it was so impressive what [Keuchel] gave us last night," Porter said. "He wasn't feeling too hot and just battled hard."
By Thursday, Porter said he could breathe a little and even felt spry enough to toss batting practice. After Porter sauntered off the diamond, Houston bench coach Dave Trembley declared, "Bo, you're a regular Lazarus, back from the dead!"