Colon was traveling to the Dominican Republic to be with his gravely ill mother, who died Monday at the age of 63 in a private clinic in the northern town of Santiago.
Adriana Colon had been battling breast cancer for several months, the Colon family said Monday in a statement via the Dominican winter-league team Aguilas Cibaenas. Colon told ESPNDeportes.com in April that she was diagnosed with cancer just before the start of the Mets' 2014 season.
With their Triple-A affiliate currently playing in Omaha, Nebraska, the Mets were unable to get an extra arm to New York for the matinee series finale against the Cubs. The Mets instead will wait until Tuesday to place Colon on the bereavement list and add an extra pitcher to supplement the bullpen.
Gonzalez Germen is expected to join the Mets from Triple-A Las Vegas for the Oakland series, a source told ESPNNewYork.com.
Germen is 2-0 with a 0.52 ERA and is 5-for-5 in save chances in 14 Pacific Coast League appearances since he was demoted July 8.