Kline is a rookie. To be more specific, he's an undrafted rookie. He saw a fair amount of time on the field and, while far from stellar, he played admirably in a hat-and-t-shirt game.
Normally, if an undrafted rookie was forced to take the field due to an injury, fans would wince and expect the worst on the field. In New England, this has just become the status quo.
All three rookies have seen considerable snaps, with Aaron Dobson and Kenbrell Thompkins leading the charge, with Josh Boyce just starting to get rolling. Unfortunately, all three are now injured to various degrees. With Rob Gronkowski sidelined, the three rookies rank as the team's 3rd, 4th, and 5th leading wide receivers on the active roster, behind veterans Julian Edelman and Danny Amendola.
Remember Zach Sudfeld? when Gronkowski was hurt, Sudfeld flopped on the field, yet still played 45 snaps in his three games with the Patriots.
Chris Barker has been mostly a healthy scratch on the active roster this season, while Josh Kline saw his first dose of heavy snaps against the Dolphins. Should any negative news come out regarding Nate Solder's head injury, look for both to be activated moving forward. The Patriots are already thin with the starting right tackle, Sebastian Vollmer, out for the season; should they lose their starting left tackle for a week, the rookies will definitely see more time on the field.
The season started with Michael Buchanan seeing snaps as the third rotational defensive end, but his edge maintenance was less than desired, which led the Patriots to bring back veteran Andre Carter. Buchanan was a stud on special teams until he was a healthy scratch against the Dolphins.
The biggest stories have to be at defensive tackle where rookies Joe Vellano and Chris Jones have seen extensive snaps while veterans Vince Wilfork and Tommy Kelly have been placed in the injured reserve.
Rookie Steve Beauharnais has received the Barker status of inactivity, while second round pick Jamie Collins has seen his snaps greatly increase in recent weeks. With Jerod Mayo out for the season, Brandon Spikes nursing a busted knee, and Dont'a Hightower struggling to move in any direction other than "forward", Collins has emerged as a bright spot for the linebackers.
Rookies Logan Ryan and Duron Harmon have seen extensive time on the field, mostly due to injuries. Ryan is playing as the fourth cornerback on the team, but is likely to see more time moving forward as Aqib Talib, Alfonzo Dennard, and Kyle Arrington all have been playing, and struggling, with injuries. Harmon stepped up when Steve Gregory went down with a wrist injury and played well enough to ease most concerns. As Gregory struggles to finish tackles, I wouldn't be surprised to see Harmon receiving more snaps as well.
Rookies Justin Green and Kanorris Davis have also seen limited snaps and played well.
Punter Ryan Allen has stepped up as a solid punter, but also as an extremely competent holder who has had to more than compensate for some of veteran long snapper Danny Aiken's more wild snaps.
That's a list of sixteen rookies who have seen extensive time on the team's 53 man active roster. Eleven of them were actively involved in the weekly game plan and were more than just practice or emergency injury bodies. That number might rise to twelve if Kline is called upon next week.
This is a testament to the front office and to the coaching staff that they've been able to field such a young and competitive team, and it speaks to how bright this team's future will be in the upcoming seasons.