The New Orleans Saints will be opening their 2015 season without safety Jairus Byrd who was unable to participate in training camp because of  a swelling knee. 

Last season, in his first year with the Saints, Byrd was limited to only four games after suffering a knee injury (torn lateral meniscus) in practice. 

In this year's offseason, Byrd participated in the Saints' organized team activities and minicamp but was placed on the physically unable to perform (PUP) list when training camp began, according to ESPN. 

Byrd is yet to practice again after being placed on the list but ESPN added that he is expected to do so soon. 

Currently the 28-year-old safety is not on the reserve-PUP list and Saints head coach Sean Payton discussed why he is not on the list and when will the possible return for the three-time Pro Bowler. 

"I think it was real simple, I don't know the exact timeline but it was as simple as just weighing six weeks or less than that if we felt like it was going to be less than that and obviously there is a strong sentiment that it is going to be less than that," Payton stated in a teleconference last Wednesday. 

Payton also said, "It was either going to be PUP or 53 but we feel confident that he is going to be playing before that six week mark."

ESPN NFL Insider Ed Werder's source said Byrd will likely be returning in Week 2 or 3. 

The Saints will open their season on Sept. 13 facing the Arizona Cardinals on the road and in Week 2 will play against the Tampa Bay Buccaneers at home, which will be followed by another road game facing the Carolina Panthers in Week 3. 

Byrd's absence is a tough blow on the Saints' defense and his replacement free safety Rafael Bush, who has also been efficient for the team, will need to step up big time.