Parks - the first man to rack up 1,000 points in the Magners League - had started the first two games but a defensive error that led to a 34-23 loss at the hands of Leinster meant Sweeney was given the nod for the following game.
And the 35-cap Wales international showed the form that helped the Blues beat Toulon in last season's Amlin Challenge Cup final as he lifted the side to a 43-21 derby win over the Dragons - leaving him grateful for the competition within the club.
"Inevitably a good team is going to want quality in each position, especially in pivotal positions," Sweeney said.
"There's room for two quality players, especially with the number of games we play and with Dan being away with Scotland.
"We have to be respectful of each other - it's not personal and hopefully we'll bring the best out of each other.
"Playing at ten you need a run of games, you need to understand the people around you and they need to understand what you're doing."