Thomas, who rushed for 1,024 yards last season despite missing three games, will take a backseat this season to Jones, who has never went over 1,000 yards in his career. Jones, a former first-round draft pick who has been a bust thus far, was given a four-year contract earlier this month.
Smith confirmed Thursday the free-agent pickup will be the starter, but Thomas will still be in the team's plans.
"Obviously it's frustrating for anybody to come in. I've been here for three years, I've been playing and they bring another guy in without sort of (telling) me what's going on," Thomas said. "I just have to take it as it is."
Jones, who was taken two spots before Brian Urlacher with the seventh pick in the 2000 draft, never panned out in Arizona and was shipped to Tampa Bay last season. He managed just 373 yards as a rookie before missing much of the season with walking pneumonia, and struggled his second year with just 380 yards. In 2002, he ran for 511 yards in nine games, but was on the shelf again late in the year with a broken right hand.
In Tampa Bay, Jones, a former standout at Virginia, was part of a running back by committee with Michael Pittman and Mike Alstott. He did start three of Tampa's final four games when Pittman and Alstott were lost to injuries and finished with a career-high 627 yards.
Now he's hoping to make a fresh start with the Bears and become the type of running back scouts envisioned he would be when he entered the league.
"They're looking for a lot from me and I expect a lot from myself, too," Jones said. "I'm looking forward to making plays."
The jury is still out on whether Jones can be the type of running back the Bears expect him to be. The team believes Jones is the right back for offensive coordinator Terry Shea's new offense, especially with Jones' speed and pass-catching ability. The Bears plan to utilize running backs downfield in the passing game and think Jones has the edge over Thomas.
Jones, 25, a 5-foot-10, 220-pounder, impressed Smith during Friday's workout -- the first for both player and coach in Chicago.
"When you look at Thomas (Jones), he gets your attention just by looking at his body a little bit," Smith said. "He's a guy that really trains well and desires to play well by the amount of training that he does.
"He's got great speed; we know that. We know he's got power, but it's good when you're in shorts to see them catch the ball and just run around and I think he did a good job with that."