Cody Ross (hip) returned to his rehab assignment Thursday after missing the previous two games with "something in his side that was bothering him," according to Diamondbacks general manager Kevin Towers. "Nothing major, just something in his side that was bothering him a little bit, so we gave him an extra day," Towers said. Ross had been slated to rejoin the D'Backs as soon as this weekend, but it's not clear whether this little setback will affect that timetable. Manager Kirk Gibson indicated earlier this week that Ross would be the main left field when he returns.