ST. LOUIS — The New York Mets placed second baseman Luis Castillo on the 15-day-disabled list today due to a strained hip flexor.

Castillo did not start the previous two games, although he played after a double switch in an 8-7 loss to the Cardinals on Wednesday. The three-time Gold Glove winner and All-Star is in the first year of a $25 million, four-year contract and has had trouble recovering from arthroscopic surgery on both knees in the offseason.

He was batting .261 in 68 games with three home runs and 26 RBIs.

The Mets, who demoted reliever Carlos Muniz on Wednesday night, purchased the contracts of outfielder Chris Aguila and second baseman Argenis Reyes from Triple-A New Orleans.

Aguila was batting .288 with 17 homers and 43 RBIs in the minors after going 1-for-6 with the Mets last month, while Reyes was batting .290 with 11 doubles, 13 steals and 22 RBIs in the minors.