However, an injury derailed his momentum, and Kowalewski found himself on the outside looking in for the majority of camp.
In his absence, both Ryan and Jason Pociask, made strong cases for themselves; each playing well during the team's first two preseason games.
The strong play of both Ryan and Pociask, coupled with the necessity of James Dearth's long-snapping ability, left the Jets stockpiled at the tight end position.
Meanwhile, Kowalewski continued to rehab, waiting for his opportunity.
"The other tight ends played great" Kowalewski said. "I felt like I had to do something to get to their level, because everyone was playing so well that, obviously, I got bumped down the line. I felt like I had to go out there and prove that I belong, that I can compete."
Kowalewski rehabbed his leg and returned to action in time to play the final two preseason games. With little margin for error, he performed well. The Syracuse alum hauled in six passes and did a good job run blocking.
With only half the preseason body of work as the other tight ends, Kowalewski left Philadelphia on Thursday night planted squarely on the bubble; not a settling feeling when your livelihood is at stake.
"I was a nervous wreck" Kowalewski said with a smile from his locker Monday morning. "This meant everything to me. Getting here, staying here, being here. I love it here. I was constantly looking at my watch, I couldn't sleep at night. I probably I stayed up until seven in the morning on Friday."
Fortunately for Kowalewski, the phone call never came.
Few believed that the team would opt to retain all five tight ends on the 53-man roster. However, that is precisely what they did.
The organization could have relegated one of the five tight ends to the practice squad, and opted to use the roster spot toward another position.
But the play of Kowalewski in the last two preseason games helped change their mind.