Strop elected free agency Wednesday, Russell Dorsey of the Chicago Sun-Times reports.
Strop has taken a personal leave of absence from the Cubs, Gordon Wittenmyer of NBC Sports Chicago reports.
Strop was returned to the Cubs' alternate training site Saturday, Tony Andracki of Marquee Sports Network reports.
Strop (1-0) worked around a hit and a walk to pitch a scoreless inning of relief and earn the win Tuesday against the Brewers. He struck out one.
Strop was selected as a replacement player by the Cubs on Monday.
Strop was optioned to minor-league camp Saturday, Jordan Bastian of MLB.com reports.
Strop has yet to pitch in a Cactus League game after being delayed by COVID-19 protocols, but he should be able to make his debut soon, Jordan Bastian of MLB.com reports.
Strop (COVID-19 protocols) was cleared to rejoin the Cubs for workouts Tuesday, Bob Nightengale of USA Today reports.
Cubs manager David Ross said Strop (COVID-19 protocols) could rejoin the team for workouts as soon as Tuesday or Wednesday, Maddie Lee of NBC Sports Chicago reports.
Strop is isolating from the team after violating the league's health and safety protocols, Jordan Bastian of MLB.com reports.