Watson suffered the injury at Thursday's practice.
The day began on a more pleasing note for Watson and Texans fans as he was named the AFC Offensive Player of the Month for October. Watson, 22, currently leads the NFL with 19 passing scores.
Watson was the No. 12 pick in the 2017 NFL Draft. He was acquired after the Texans traded their first-round pick in 2017 and first-round pick in 2018 to the Cleveland Browns in order to move up in the first-round of the 2017 NFL Draft.
"They say you never miss it until it's gone and even though it's not gone for long, I already miss it," Watson wrote using the notes app on his phone, before posting the message to Twitter. "Yesterday I felt like I let my teammates, my fans and my family down. However, as a child of God, I understand that everything happens for a reason. He don't make mistakes!"
"Today, the journey back seems far but I've been here before and will conquer it once again. I want to thank each and every one of my teammates for their unwavering support. My NFL brothers, thanks for all the prayers. To my fans, I cannot begin to express my gratitude for your relentless encouragement. To the countless others who have reached out, I am humbled and can only say thank you from the depths of my heart. I play this game for you all, and I am grateful for the love you have shown me, not only over the past 24 hours, but throughout this entire season."
"I promise that I will continue to work diligently so that this team can one day bring a championship to Houston, and when I return, I will be better, stronger and more focused than ever before! Now the grind begins....#815 #memo Godspeed. A small thing to a giant."
"He will be one of the top quarterbacks in this league for a long time to come."
Watson was hurt in the first team period during a non-contract drill at Thursday's practice session.
Watt is also out with a season-ending injury.