The Astros announced the deal and his promotion Monday during an off day. Houston plays host to the Angels on Tuesday night.
Singleton is rated by many as baseball's top first baseman of the future. His new deal runs through the 2018 season with club options for the following three seasons. Financial terms weren't disclosed.
The 22-year-old was hitting .267 with 14 home runs and 43 runs batted in for triple-A Oklahoma City.
Singleton was acquired from Philadelphia in the 2011 trade for
The New York Mets put center fielder Juan Lagares on the 15-day disabled list because of a ribcage injury and recalled outfielder Matt den Dekker from triple-A Las Vegas.
Den Dekker started in center field Monday night and led off in the finale of a five-game series against the Philadelphia Phillies.
Lagares is hitting .288 with two home runs and 18 RBIs. Den Dekker was 0 for 4 in three games with the Mets before being sent to triple A on Sunday.