Tightness of the IT band causes femoral internal rotation and tight peroneal also causes tightness of the IT band. A dynamic foot assessment single leg stance to assess hip musculature can give clarity as to why IT is tight. Stretching with MCT foam roller would help.
strengthening the hips abductors and stretching the peroneal muscles will help avoid future issues.
I agree with all the suggestions and stretches given above. Just thought of adding some relevant issues associated with IT band. This type of tightness usually happens unilaterally.
I could not agree more with all the recommendations on assessment.
I would like to offer a suggestions to massage the fascia of the IT band using the MELT method: Use a SOFT foam roller (no, definitely not the hard ones; more pain is NOT better). Sit on the roller and place it just below the greater trochanter on the posterior side of the IT band. You can be on your elbow or wrist, and you should place the other leg in front of the one you are treating. Slowly roll down towards the knee, stopping at barriers. You may even bend and extend the leg on the roller if you can tolerate it. Once your have made it close to the knee, roll half over towards your stomach so that the roller is now near the knee on the anterior side of the IT band. Gently roll back up towards the hip, then roll over again towards the starting position and now go down in a smooth motion. Repeat that a few times. It is as if you are making a big oval, going down posteriorly and up anteriorly the IT band but not being directly on top of it.
To repeat: do not use a hard roller, this can do more harm than good.