Already in the third phase of the OTAs, the Dallas Cowboys still don’t have the presence of their main receiver. Dallas picked up the fifth-year option on the CeeDe Lamb’s rookie contract, but the front office has already expressed a desire to extend his stay by a few years. On Tuesday, the mandatory minicamp began and the wide receiver didn’t show up. He’s committed to continuing with his holdout, whatever the cost – literally. What’s at stake if Lamb doesn’t take part in mandatory activitiesAlthough the OTAs are voluntary, the off-season is reaching the point where practices become compulsor…