During the month of September 2007, the Mets were in a freefall as they tried to hold off the Phillies in their pursuit of a second straight Eastern Division title. The bullpen was in shambles and they looked for help anywhere they could find it, one of the people they looked toward was Carlos Muniz. After spending 5 seasons in the Mets minor league system right-handed pitcher Carlos Muniz made his Major League debut on September 25, 2007, he pitched 1 1/3 innings of relief and allowed 2 earned runs. He made one more appearance four days later, pitching a scoreless 9th inning in the Mets 13-0 win over the Florida Marlins. But unfortunately, the Mets lost the next day to complete one of the worst collapses in baseball history.
Muniz spent the 2008 season shuffling between triple A New Orleans and New York. He appeared in 18 games out of the Mets bullpen and posted a 1-1 record with a 5.40 ERA in 23 1/3 innings. His one victory came on July 12 against the Colorado Rockies.
Muniz spent the next two seasons pitching in the Mets minor league system before leaving to pitch in Mexico. In 20 games over two seasons for the Mets Muniz posted a 1-1 record with a 5.61 ERA.
While with the Mets Muniz wore number 38 in 2007 and 32 in 2008.