Set to open their 2016 training camp this coming week, the Ravens announced Saturday that six players would begin the summer on the active physically unable to perform list.Wide receivers Steve Smith (Achilles tendon) and Breshad Perriman (knee), linebackers Terrell Suggs (Achilles tendon) and Elvis Dumervil (foot surgery), running back Trent Richardson (knee), and cornerback Jumal Rolle (Achilles tendon) were placed on the PUP list ahead of Wednesday’s report day for veterans. Rolle is expected to miss the 2016 season after suffering a torn Achilles tendon during a spring workout.Head coach John Harbaugh indicated during last month’s mandatory minicamp that the Ravens would be careful with the workload for Smith, Suggs, and Dumervil during training camp and even in preseason games as they work their way back to full strength. After suffering a left knee injury originally feared to be a season-ending ACL tear in June, Perriman is expected to return at some point during training camp, according to Harbaugh.Signed to compete for a roster spot with a deep group of running backs, Richardson was hampered by a hamstring issue during organized team activities and underwent knee surgery last month.Often confused with the reserve list that requires a player to miss the first six weeks of the regular season, active PUP is used for any player who isn’t ready to begin practicing at the start of training camp. Players on active PUP may return to the field at any point, but that activation makes them ineligible for the reserve list that doesn’t count against the 53-man roster limit to begin the regular season.It’s worth noting that quarterback Joe Flacco (knee), cornerback Jimmy Smith (foot surgery), cornerback Will Davis (knee), and wide receiver Michael Campanaro (calf) were not placed on PUP, meaning they should be ready to begin practicing immediately. Flacco said during last month’s minicamp and reiterated this past week that he would be back on the field for the first day less than eight months after undergoing ACL reconstruction surgery on his left knee.