Alexander Rossi says he turned down the opportunity to race for Manor for the rest of the 2016 season as he wants to focus on IndyCar.
The American drove for Manor in five of the final seven races in 2015 and impressed, but failed to land a full-time seat for this season. Instead moving to IndyCar, Rossi went on to win the Indy 500 on debut and is currently 11th in the standings after four top ten finishes.
With Rio Haryanto struggling to secure the required funding from the Indonesian government to keep his seat, Rossi - Manor's reserve driver - was offered first refusal on the seat but opted to remain in IndyCar, which clashes with the next three grands prix on the calendar.
"My management and I are in constant communications with Manor and we knew there might be an opportunity to race for the last half of the 2016 season," Rossi told Autosport. "We gave it careful thought but declined the race seat due to my IndyCar contract.
"I have a lot of respect for Manor giving us first right on the seat as we agreed. I have a really good relationship at Manor and there are no hard feelings. They understand an F1 deal has to be right for my future and my career has taken some good steps forward."
And Rossi says he has held talks with teams in both F1 and IndyCar for next season, but is yet to make a decision on which series he will race in.
"I have options both in IndyCar and Formula 1 for 2017. There have been talks with Manor for a race seat and we've also been approached by another F1 team that's quite interesting.
"There are options in IndyCar that I can't elaborate on, but I can say Andretti and I have a great working relationship. Everyone at Andretti is aligned and working in good faith to extend our deal for several years.
"There's a sense of loyalty to Michael [Andretti], his team and Honda. As a driver there are some really good opportunities here and the competition is fantastic."