Diamondbacks manager Torey Lovullo said Wednesday that Lawlar recently aggravated his strained left hamstring and will be sidelined an additional 6-to-8 weeks, Jesse Friedman of GoPHNX.com reports.

The 22-year-old began a rehab assignment in the rookie-level Arizona Complex League over the weekend, but quickly aggravated the hamstring injury he suffered in mid-June. Lawlar has played in just four games for Triple-A Reno this season due to injuries and won't be back on the field for the Aces anytime soon. A return in late August is likely the best-case scenario in what's shaping up to be a lost campaign for the Diamondbacks' top prospect.