He either died or married after 1624, as his name no longer appears in the membership lists of the St. George militia after that. He was probably related to Cornelia Jansdr. Vlasman, who married the painter Floris van Dyck in 1625.
Gerrit Cornelisz. Vlasman in De Haarlemse Schuttersstukken, by Jhr. Mr. C.C. van Valkenburg, pp. 67, Haerlem : jaarboek 1958, ISSN 0927-0728, on the website of the North Holland Archives