21-year-old Lynch goes straight into the squad that faces Crawley Town at Moss Lane tomorrow night after Macclesfield Town had recalled James Jennings.
The loan spell will end on Wednesday 9 April but the Robins will have an option to extend if the Solihull born defender impresses.
Lynch who signed a one-year deal after being released during the summer from Coventry City has already had a loan spell at Stafford Rangers earlier on in the season and made two appearances for the Marston Road club,