"The biggest thing is his preparation," Thibodeau told ESPNChicago.com on Thursday. "I'm very excited about the way he came back after the season was over. The way he worked to get ready to play in the summer league this year was entirely different than his rookie year and that's understandable when you have a 19-year-old kid coming in.
"I don't think he really understood what he was going to be facing. After going through the league for a year, he went home, got a couple weeks off and then he went right into the gym, put a lot of work in and it showed."
Teague is fifth in the Las Vegas Summer League with 18.3 points a game along with 4.8 assists. He has also connected on 6-of-8 three-pointers.
Drafted No. 29 overall in 2012, Teague played sparingly as a rookie, appearing in 48 games. But as the injuries mounted in the playoffs, Teague got some meaningful minutes in Game 7 of their first-round series against the Brooklyn Nets and then averaged 12.5 minutes a game in the next round against the Miami Heat.
The Bulls hope Teague can make the leap from his first to second season like Jimmy Butler did last season.
"I think the big thing for him is to build confidence," Thibodeau said. "This is really the first step toward next season so as we saw with Jimmy last year, Jimmy did the same thing. Season ended, he came in, started working, had a great Summer League, came back to Chicago, continued to work, great fall practice, great training camp and was ready to roll. Hopefully that will be the case with Marquis."
ESPNChicago.com's Nick Friedell contributed to this report.