Hanhold was recalled from Triple-A Syracuse on Saturday.
Hanhold made three appearances for the Mets last season, giving up two runs in 2.1 innings, and has a 3.60 ERA in 15 innings for Syracuse this season. Justin Wilson (elbow) landed on the injured list in a corresponding move.
The Mets optioned Hanhold to their minor-league camp Saturday.
Hanhold received his first cup of coffee with the Mets last season, appearing in three games out of the bullpen. Though the Mets kept him on the 40-man roster through the offseason, the 25-year-old wasn't viewed as a serious contender to break camp with the big club. Expect him to open the 2019 campaign at Triple-A Syracuse.