The Mets recalled Stewart from Triple-A Syracuse on Monday, Will Sammon of The Athletic reports.
With J.D. Martinez set to miss the next several games while on paternity leave, Stewart will now come up from the minors to fill the open roster spot and could step in as the Mets' designated hitter. Since being sent to Syracuse in July, the 30-year-old has slashed .275/.444/.435 across 90 plate appearances at Triple-A.