Following their victory in St. Louis this afternoon, the Mets recalled Kirk Nieuwenhuis from Triple-A Las Vegas and optioned Matt den Dekker there to make room for him on the active roster. Both players have split time with Vegas and the Mets, though each player has played significantly more with the 51s.
For what it's worth, Nieuwenhuis has been the better hitter with Vegas this year. He's put up a .272/.318/.539 slash line there with 10 home runs, while den Dekker hit .269/.326/.421 with 4 home runs. Nieuwenhuis managed a 100 wRC+ in the 21 plate appearances he had with the Mets earlier this year, but den Dekker really struggled and had just a 22 wRC+ in 49 plate appearances.
In total, there's not a ton of difference between the two players. If the rest of the Mets' outfield stays healthy, Nieunwenhuis takes den Dekker's spot as the seemingly obvious demotion once Juan Lagares returns from the disabled list.