The Cubs also want to continue to assess him against quality pitching, Sveum said.
"He's down there to develop and just be consistent," Sveum said. "More importantly, it's just the quality and the consistency on a daily basis swinging the bat -- instead of a day-to-day thing, like good, bad, good bad."
While Jackson might not be called up, Dave Sappelt could be brought back up to the Cubs to help fill in for David DeJesus, Sveum said. Sappelt is hitting .248 with two home runs 21 RBIs for Iowa.
Sappelt has played in 20 games for Chicago this season, and is hitting .178 (8-for-45).
Chris Iseman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.