The Denver Broncos managed to bring in some stability under center with the signing of quarterback Case Keenum this NFL offseason. His arrival has brought a newfound sense of optimism to Denver following a stellar stint with the Minnesota Vikings.

However, there is still the matter of who is going to back him up. According to Nicki Jhabvala of The Athletic, quarterbacks Paxton Lynch and Chad Kelly have done little to separate themselves from each other.

But four days into training camp, neither has pulled away. Neither has instilled a confidence to outsiders that he could be the reliable backup — a position crucial to a deep playoff run (see: Nick Foles and the Super Bowl champion Philadelphia Eagles).

While Denver's concerns are precautionary, it is a situation they will have to monitor throughout the year closely. It is undoubtedly essential to have a competent starting quarterback. However, the Philadelphia Eagles proved last season how vital it was to have a viable backup option.

Perhaps the more significant concern here is the lack of progression from Lynch. The Broncos made quite the investment when they selected him with the 26th overall pick in the 2016 NFL Draft. Unfortunately, he has yet to show any signs of becoming a potential starter.

Regardless, general manager John Elway has expressed his confidence in Lynch on a number of occasions. Elway's patience could be wearing thin if he is unable to at least establish himself as the backup over Kelly, who still has yet to make an appearance after being taken in the seventh round of the 2017 NFL Draft.