As a veteran pitcher on a rebuilding team, Jackson's name had come up during the run-up to last week's non-waiver trade deadline. It was reported that the Cubs were trying to trade the starter but couldn't find teams interested in him.
Jackson has a 5.79 ERA in 22 starts this year. He has two years and $22 million remaining on his contract after this season.
Since the non-waiver deadline has passed, the Cubs would have to expose Jackson to waivers in making any potential deal. The waiver trade deadline is Aug. 31.
"I don't know how many times I can say it," Jackson said. "I say it with a smile. I say it without a smile. I worry about what I can control. Other than that, I have a job, and my job is to be prepared for the next start."
The Cubs made several deals before the deadline, trading second baseman Darwin Barney to the Los Angeles Dodgers, sending utility man Emilio Bonifacio and reliever James Russell to the Atlanta Braves and acquiring pitcher Felix Doubront from the Boston Red Sox.
- Ben Estes