He had taken a foul ball of his foot while behind the plate, and Mets general manager Sandy Alderson confirmed the injury -- a non-displaced fracture of the first metatarsal -- with reporters in Denver, where the Mets are in the midst of a series with the Rockies.
According to Metsblog.com, Alderson indicated that d'Arnaud is in a walking boot and will fly to New York to visit team doctors at the Hospital for Special Surgery for further evaluation.
d'Arnaud initially stayed in the game after being attended to by the club's athletic trainer, Joe Golia, as manager Wally Backman observed. d'Arnaud was, however, replaced a half inning later by pinch hitter Landon Powell. Las Vegas went on to win, 3-2.
When the incident occurred, Sacramento's Tyler Ladendorf was at the plate as 51s pitcher Adam Kolarek broke off a 1-2 curveball that Ladendorf fouled off d'Arnaud's foot.
Las Vegas broadcaster Russ Langer described the play.
"That got a piece of d'Arnaud, who is face down on the ground," said Langer on the broadcast. "He is face down on the ground, and now he goes into a push-up -- ouch."
The incident can be viewed at the 1:43:55 mark of the MiLB.TV archive.
d'Arnaud is in his second season with the 51s, which became the Mets' Triple-A affiliate this year. He is batting .250 with one home run, eight RBIs and a .429 on-base percentage in 12 games.
Before missing the latter half of the 2012 season with a knee injury, d'Arnaud hit .333 with 16 homers and 52 RBIs in 67 games with the 51's.
Considered the Mets' catcher of the future, d'Arnaud -- MLB.com's No. 6 prospect -- was part of the package New York received from Toronto in the R.A. Dickey deal this past offseason. He was acquired by the Blue Jays from the Phillies in a 2009 trade for another Cy Young Award winner, Roy Halladay.
d'Arnaud batted .246 in 16 Grapefruit League games this spring, and with catcher John Buck off to a red-hot start in New York, the Mets have seen no reason to rush the prospect.
Mets manager Terry Collins did not rule out using both d'Arnaud and Buck in the lineup, but added that d'Arnaud is not yet ready.
"I talked to [Las Vegas manager] Wally Backman the other day and asked how d'Arnaud was doing, and he said he has to play a little more every day," Collins told the New York Daily News Wednesday.
Any plans to promote d'Arnaud are now on hold. Foot fractures typically take players out of action for six to eight weeks.