Sergio Aguero accepts Manuel Pellegrini has a major decision to make as to whether Manchester City risk their Golden Boot winner against champions Chelsea.
The striker, who scored 26 Premier League goals last season, came on for the final 27 minutes of City's 3-0 win against West Bromwich Albion on Monday.
But, after missing City's preseason games, it was his first football since the Copa America final and Aguero admitted he is in a race against time to be fully fit for Sunday's clash with Jose Mourinho's team.
"Whether I start or not remains to be seen," Aguero told City's website. "I'm trying to get there and be in top condition, but arriving for pre-season later having taken part in the Copa America with Argentina means I need some additional time."
Manager Pellegrini, who saw Aguero's 2013-14 season interrupted by injury, is adamant his players have at least 28 days off in a summer and prefers to ease the former Atletico Madrid forward into a campaign in an attempt to stop him being sidelined again.
"With the whole season in mind, what matters the most is that I get in top form and don't take any risks," Aguero added.
Sunday's match pits the last two Premier League winners against each other, but Aguero feels that other sides are also possible champions.
He said: "One thing you can say about the Premier League is that every year, it gets better.
"Once again, many teams have made very important additions and that means there's no single rival for us this season.
"It'd be very naive to think that Chelsea will be the only team competing for the top position -- there will be many of us and each one will challenge in their own style."
A win for City would put them five points ahead of Chelsea, who drew 2-2 with Swansea in their opening fixture.
And Aguero added: "Beating Chelsea would be fantastic because it's always better to have a head start, but I don't think we should focus on just the early stages.
"The season is long, we have to be ready from the word go to the very end and try to maintain as much momentum as much as possible."