Keuchel, who threw three innings Monday in Oklahoma City's season finale, will start for the Astros on Monday at home against the Cubs. He will be available to work out of the bullpen and could get an inning Friday in Cincinnati.
"The overall plan is to give these guys an extra day with a day off toward the end of the season," interim manager Tony DeFrancesco said. "We have a lot of young arms we don't want to get overworked with Jordan and Harrell. Bud [Norris] has been a horse all year, and we want to make sure at the end of the year we have a chance to evaluate all these pitchers to see who's in line at the end of the season."
Lyles entered his start Tuesday against the Pirates with 154 1/3 combined innings this year between the Astros (113 2/3) and Triple-A Oklahoma City (40 2/3). His career high innings pitched in pro ball is 158 2/3 in 2010 at Triple-A Round Rock and Double-A Corpus Christi.
Harrell, meanwhile, has pitched a career-high 165 frames this year. His previous high workload came in 2010 with 161 2/3 innings combined between Triple-A Charlotte and the White Sox.