By Tzvi Machlin The Baltimore Ravens have begun their voluntary OTA practices today. But their most notable player isn’t there. Per Ravens insider Jamison Hensley, quarterback Lamar Jackson is not participating in this week’s OTAs. He’s one of 17 players on the roster who is skipping it. Jackson is currently involved in a contract dispute with the Baltimore Ravens. The Ravens reportedly made Jackson a contract offer earlier this offseason, but Jackson didn’t accept it. Jackson doesn’t have an agent either. He works with friends and family to make contract decisions. That might be part of what …