I don't think Putin cares about Gerasimov. If Yevgeny Prigozhin shoots Gerasimov, it's just collateral damage to Putin.
It’s humiliating for Putin if Wagner captured his top general in Rostov. The rumor was that Gerasimov fled the Southern Military District HQ before Wagner arrived and was hiding at a friend’s apartment in the city. Not a good look if true.