The right-hander has spent almost the entire season on the disabled list with a rotator cuff strain.
Cashner, who suffered a setback in mid-May, said he's targeting an early September return to the Cubs' bullpen.
"I've been ready to go for a while now and I'm looking forward to the opportunity to get back on the mound and start playing again healthy," Cashner said after throwing a bullpen session on Sunday.
Cashner expects to work just the first inning of Tuesday's game against the Chattanooga Lookouts before making another three or four appearances with the Smokies, possibly both starts and relief work, before moving up to Triple-A Iowa.
Cashner allowed a run and two hits over 5 1/3 innings in his season debut. As a rookie last season, he appeared in 53 games as a reliever.
Chris Silva is a contributor to ESPNChicago.com.