Purse had to make do with a place on the bench after Upson joined from Arsenal in February and formed a superb partnership at the heart of the Blues defence with Kenny Cunningham, but he aims to fight to win his place back in manager Steve Bruce's starting eleven.
"Last season has gone," Purse told the Birmingham Post.
"Towards the end Matty and Kenny were playing superbly so you just have to bide your time and wait for your chance.
"Hopefully if I get a chance in the first game of the season and play well, the gaffer will have a difficult decision to make.
"I've got to get in the side first and that's my aim for the beginning of the season.
"This pre-season I've come in and tried to get as fit as possible and be ready for that first game. If selected you just have to be ready and I've been trying to stay injury-free and get in that side."
