Targett, who has not played for nine months, admitted that his time on the sidelines has been tough to take.
The 28-year-old suffered a hamstring injury last November and then tore his Achilles.
"It's been tricky," he told NUFC TV, after returning to the bench for their first game of the season against Southampton.
"Obviously, with the operation on the hamstring, you're getting your head around that so you have your targets, when your return to play dates are, and I got back just before the March or April international break. That was always the aim and then after that you get a tear in your achilles so you have to stop again.
"It was frustrating. The whole season was frustrating. When you look at the start of the season, it's full of excitement, especially with the Champions League. You think there are so many opportunities with the amount of games we had so to not be available for them was difficult.
"It's not a nice feeling. You want to be there for your team-mates, you want to be there for the coaching staff, and it's so frustrating when you're not available."