James told reporters it was incumbent on the entire team to perform rather than relying on Thomas:
"To be honest, I don't think it's too much expected. I don't think we're relying on IT to come back. We want him to take his time. When he feels he's ready, he's going to fit right in. We can't rely on just one person. We can't rely on just one person for us to be as good as we want to be, whether it's IT or myself or Tristan [Thompson] being out. We have guys who have to step up."
Thomas has yet to play this season due to a right hip ailment. Per Tom Withers of the Associated Press, it is possible he could return earlier than the initial timetable of late December.
James added: "IT is definitely a big piece of what we want to do, but IT hasn't stepped out on the floor in a Cavs uniform yet. We know what he's capable of doing, but he hasn't played with us, so we don't want to put that type of pressure on him, even though he loves it."
Cleveland dealt guard Kyrie Irving to the Boston Celtics to acquire Thomas in an offseason trade, also picking up Jae Crowder, Ante Zizic, the Brooklyn Nets' unprotected 2018 first-round draft pick and the Miami Heat's 2020 second-rounder.
While Irving has helped Boston to an NBA-best start of 10-2, the Cavaliers have scuffled thus far to the tune of a 5-6 record.
Thomas' arrival could be huge for Cleveland, though, as he was named an All-Star in each of the past two seasons.
In 2016-17, Thomas set a career high with 28.9 points per game to go along with 5.9 assists and 2.7 rebounds as the top player for a Celtics team that earned the No. 1 seed in the Eastern Conference.
The Cavs will look to get back to .500 without Thomas on Thursday night when they face the Houston Rockets.