Notts' new skipper Stephen Fleming is playing for New Zealand against Sri Lanka, so Gallian has retaken the captain's armband that was his from 1998 to 2004.
He said: "I'm delighted to take the reins again and I'm relishing the chance to captain the side for the first game of the season.
"We've had some great tussles with Middlesex in the past and we'll be taking on one of the world's in-form batsmen in Andrew Strauss, but we're confident we have the team and tactics to get a win under our belt."
Fleming arrives in England next week and his first game in charge will be against Middlesex in the Championship at Lord's, starting on April 20.
THURSDAY 21 SEPTEMBER 2017
ENGLAND v WEST INDIES