Stefon Diggs appeared to be on baby duty earlier this year -- the NFL superstar was spotted leaving a hospital with a car seat in his hands ... exactly one day before he hard-launched his relationship with Cardi B.
TMZ Sports has obtained footage of the New England Patriots receiver outside an NYC medical facility on May 11 ... meaning he really made the most of his time in the Big Apple, as he hit Madison Square Garden hand-in-hand with the "Outside" rapper to catch the Knicks host the Boston Celtics in a playoff matchup just over 24 hours later.