Nicky Hayden got his second home event of the season off to a promising start with third in a slippery FP1 session at Indianapolis.
However the Ducati star then dropped to ninth in the quicker afternoon outing.
“This morning when the track was dirty, it was good for me. It helped me a lot,” explained Hayden. “This afternoon, everybody went quite a bit faster, and I didn't do a big step.
“But I'm thinking the bike is definitely better here. We have a better chance of putting up a better fight here than we did at Laguna Seca. At least that is my hope. We'll see on Sunday,” added Hayden, who finished seventh in the US GP.
Hayden finished practice one place ahead of team-mate Valentino Rossi and was asked for his thoughts on the Italian's end-of-season departure.
“Maybe that's a good thing. It will maybe take a little pressure off of everybody, and we can focus on our job. It's going to be a lot different, for sure,” he replied.
“There were certainly some positives of having Valentino around, but maybe we can also use it to an advantage. You know, I was sad to see him go. I enjoyed being team-mates with him, but I also look forward to new challenges.”
Rossi lapped 1.7s behind Repsol Honda's Dani Pedrosa on Friday.
“We have to go faster. The [improving] track can help us with that a bit,” said Rossi, who will return to Yamaha next season. “I lose a lot in the exit of the two hairpins in acceleration because the other guys are able to use less electronics and put more horsepower on the ground. We will work on this.”