Jackett's men came through their latest friendly with a 3-1 win over Bohemians thanks to two goals from Leon Clarke and one from Nouha Dicko, but the manager conceded that the players struggled to adapt to the constant changes to the side.
Speaking to the club's official website, Jackett said: "You could see a team in the first half but in the second we had to develop it and work it.
"While individuals did well it showed that when players are thrown together the development doesn't always come and it is difficult as a one-off.
"I wanted to look at the partnership of (Ethan) Ebanks-Landell and (Sam) Ricketts and see how they did.
"For me the partnership of Ebanks-Landell and (Kortney) Hause might be a little bit young for the league so I wanted to give Ethan a go with an experienced partner beside him.
"Although it is pre-season and our season hasn't started yet, I am looking to use my experience to feel how certain players will do, working at different situations and different combinations."