Maguire hurt his hamstring in the Republic's goalless draw with Northern Ireland in Dublin on Thursday night a few minutes after coming on as a substitute.
He is travelling back to Preston to have the extent of the injury assessed.
Browne was in Martin O'Neill's squad for the two games during the international break but didn't make the matchday squad against Northern Ireland.
A shoulder injury has now forced him to withdraw from international duty, an injury it is understood he has been carrying for a little while.
Callum Robinson is the one remaining Preston player in the Republic of Ireland squad.