Robert Gsellman was the first visitor to use the Nats' bullpen cart, as Sean Doolittle looked on carefully

The revival of the bullpen cart has been a highlight of this season, for sure. Few players have embraced its return to MLB more than Sean Doolittle, who was the proud first passenger in the Nats' cart earlier this month after being an outspoken member of the pro-cart lobby. 
Being the first Nats player to use the team's cart, and the second pitcher overall to use the D-backs' new cart this season, Doolittle has a strong sense of pride associated with it ... and maybe feels a bit possessive about it?
In the Nats' 5-4 loss to the Mets at Nationals Park on Thursday, New York's Robert Gsellman became the first visiting player to use the cart for his entrance into the game. Warrming up in Washington's bullpen, Doolittle just wasn't sure if he liked what he saw:

To reclaim his status as premier Nats cart user, Sean then rode it out to the field before taking the mound in the ninth inning. 
This was all in good fun, of course, but can you blame him? He's not the only player to experience the magic of the Nats' bullpen cart anymore.
Sharing is hard.