NASHVILLE – The Titans are set to open training camp with three players on the team's Physically Unable to Perform list – defensive lineman Jurrell Casey, tight end Jonnu Smith and kicker Ryan Succop.

All three players were placed on PUP on Monday.

Also, defensive lineman Jeffery Simmons has been placed on the team's NFI (Non-Football Injury) list.

Casey and Smith are recovering from knee injuries suffered at the end of last season. Succop, meanwhile, hasn't practiced throughout the offseason as he recovers from an injury as well.

Each of these players will be eligible to practice with the team upon passing a physical.

The Titans begin training camp on Friday. The reporting date for all players is on Thursday, although rookies, quarterbacks and all players who ended the offseason injured reported to Saint Thomas Sports Park on Monday.

The good news is several Titans who were limited during the offseason with injuries – including tackle Jack Conklin, tight end Delanie Walker, cornerback Adoree' Jackson and cornerback Logan Ryan – are not listed with injury designations at the start of camp. There's a chance some of those players could still be limited, however.

Simmons, the team's first-round draft pick, suffered a torn ACL during a workout in February and is rehabbing at Saint Thomas Sports Park.

Rules related to the PUP list:

Players who start the preseason on the PUP list may not practice until cleared by team medical personnel. They can attend team meetings and work out, however, and once cleared they can return to the field.

Players who practice during training camp are not eligible for the PUP list.

If a player finishes preseason on the PUP list, they can be placed on the regular season PUP list.

Players on the PUP list do not count against the 53-man roster, but do count against the 90-man roster limit.

The non-football injury list is for players who suffer an injury not related to NFL football or and keeps players from practicing at the start of training camp. The NFI covers injuries sustained during a player's final college football season.