There are lots of studies done about the benefits of yoga for athletes and those that train using CrossFit.
“Research shows that the two types of individuals most prone to injury are individuals who are too flexible and individuals that are too tight. The first causes laxity in the joint, the latter causes problems such as loss of range of motion and pulling of the musculature on the skeletal structure causing improper alignment. With that said, I would recommend an individual supplement CrossFit with a yoga practice about twice a week.” By Tim Huntley from myathleticlife.com
Here is another article by mindbodygreen.com