The Giuseppe Meazza side secured the services of Hernanes from Lazio during the January transfer window, while it announced the capture of Nemanja Vidic on a Bosman move earlier this week.
Nevertheless, Thohir has promised Inter's fans that there will be more high-profile arrivals before the start of the 2014-15 campaign.
"We might add a few players for next season. We're building a team for the next few years," Thohir was quoted as saying on the club's official website. "With Hernanes I think we have leadership in the middle. With Vidic we have a leader in the defense.
"I think we need to create stability in the team but I think by next season the average age of the team will be 26.5 years old. The most important thing, as I keep saying, is to balance the ages and also balance the positions."
Inter currently sits fifth in the Serie A table with 41 points from 26 games.