The Cubs will exercise Hamels' $20 million option for 2019 on Friday, Jerry Crasnick of ESPN.com reports.
Hamels was dealt to the Cubs at the July trade deadline and posted a 2.36 ERA, 1.10 WHIP and 74:23 K:BB in 12 starts, which was enough for the team to bring him back for 2019. The veteran left-hander hasn't posted a sub-3.00 ERA for a full season since 2014, so a repeat of those numbers doesn't seem particularly likely, but he certainly found a resurgence in Chicago after having 4.72 ERA and 1.37 WHIP through the first half of the season with Texas.