In his first three games this season, before Rex Grossman suffered a season-ending knee injury, Jones rushed 66 times for 329 yards, a 5.0-yard average.
Through the Bears' first six games, Jones ran for 510 yards on 116 carries, still a very respectable 4.4-yard average. But since then, he's carried 76 times for 221 yards, a miserable 2.9-yard average.
Jones suffered a sprained toe on his first carry in the seventh game of the season and missed the remainder of that contest and the next two. He hasn't averaged more than 3.3 yards per carry in any game since his return although he says the injury is completely healed.
"I don't know the answer to Thomas Jones right now," offensive coordinator Terry Shea said. "I think it has everything to do with our offense, and the fact that we're just not playing well enough from one position to the next."
It's not just that Jones isn't getting the yardage he did earlier in the season, he's not getting the ball as often, something that Shea has been criticized for. Jones hasn't carried more than 18 games in any of the last nine games. An ineffective passing game has allowed opposing defense to focus their attention on stopping Jones, and big second-half deficits have rendered the running game moot.
"When Rex was out there we had a good relationship, a good chemistry together," said Jones, who after six games was on pace for 1,360 rushing yards. "When he was hurt a new guy came in and it was a different situation, and the defenses put eight guys around the ball, so I had to run the ball against eight or nine guys right there in your face as soon as you get the ball."
Now it's highly doubtful that Jones will even reach 1,000 yards. He'll enter Sunday's penultimate game with 731 yards on 192 carries.
Last week the Bears ran the ball eight times for five yards in the second half. A week earlier, in the 22-3 loss to the Jacksonville Jaguars, the Bears ran twice for two yards.
"When you carry the ball 13 times, or the team only runs 14 times, twice in the second half, it's not even a running game at all," Jones said. "It's tough, but you just have to do what you can do in the second half."
Although his numbers and the team's fortunes have plummeted in the last two months, the 26-year-old Jones doesn't consider for a second that he's not much better off with the Bears than he was in his first three NFL seasons.
After being drafted seventh overall in 2000 by the Arizona Cardinals, Jones almost felt as if he were wasting away in the desert before parlaying one solid season with the Tampa Bay Bucs into a $10 million deal with the Bears.
In Arizona, sometimes Jones started, sometimes he didn't. At times he was the featured ball carrier, other times he wasn't.
"This is different because here I'm in a position where I can do what I'm here to do," he said. "I'm here to run the ball.
"In Arizona, I was in an organization that wasn't the best to me, and we didn't win too many games. I wasn't in a position to contribute to the team, so that's why it was the worst situation for me."