The Cubs optioned Thompson to the Arizona Complex League on Friday, Andy Martinez of Marquee Sports Network reports.
Following the activation of Adbert Alzolay (forearm) from the 15-day IL, Thompson will be pushed off the active roster and continue working at the Cubs' facility in Arizona. He holds a 4.71 ERA and 1.36 WHIP through 28.2 innings on the year, and he could end up being a bullpen depth option in the postseason should the Cubs secure a spot.