d'Arnaud is scheduled to see a doctor before Tuesday night's game.
"I felt it bark up," said d'Arnaud. "I decided to say something. We'll find out more tomorrow. I've never experienced it before. That's why I said something, just to be safe."
Cincinnati's baserunners took advantage of Syndergaard's occasionally deliberate time to the plate, but d'Arnaud noticeably hurried the final attempt, a sixth-inning steal of second by Ivan de Jesus, yanking the throw to the shortstop side of second base. A half-inning later, d'Arnaud grimaced after fouling off a pitch. He singled later in the at-bat.
d'Arnaud played in 67 games in 2015 due to injuries to his right pinky finger and left elbow. He was forced to leave a game during his rookie season in 2013 after being hit by a foul ball on the left shoulder, but he did not miss significant playing time due to the injury.
d'Arnaud is hitting .196 through 13 games this season with zero home runs and one RBI.
"Any time you talk about a shoulder problem with a catcher, it's a problem," Collins said. "I think it's too early to say … but, yeah, I'm always worried about that."
Joe Trezza is a reporter for MLB.com based in New York. Follow him on Twitter at @joetrezz. This story was not subject to the approval of Major League Baseball or its clubs.