The top 50 in the rankings the week before the Masters earn invitations to Augusta National, and the four aforementioned names were the only ones in the top 50 who weren't already qualified.
Lahiri, No. 33, has won twice this year on the European Tour at the Maybank Malaysian Open and the Hero Indian Open. He'll be competing in his first Masters.
Grace, No. 41, won in January at the Qatar Masters and will be making his third trip to Augusta, following a T-18 in 2013 and a missed cut in 2014.
Wiesberger, No. 42, became known to American audiences last year with his impressive showing at the PGA Championship, ending in a T-15 finish. The first Austrian to ever compete in a U.S. Open when he missed the cut last year at Pinehurst, he'll also be competing in his first Masters.
Casey, No. 48 and a long-time European Tour stalwart, made the commitment to play the PGA Tour full-time this year. He nearly broke through for his first Tour victory since 2009 when he lost a playoff back in February at Riviera. He's headed back to Augusta for the first time since 2012. In eight Masters appearances, he's notched two top-10s, a T-6 in 2004 and a T-10 in 2007.
Non-invitee bubble boys who failed to crack the top 50 include No. 51 Marc Warren, No. 53 Harris English, No. 57 Alexander Levy and No. 58 Andy Sullivan.
The Masters field is now up to 99 players. Should the winner of next week's Shell Houston Open earn a berth and should Tiger Woods announce he's playing, the field could expand to 101. It would be the first time the Masters has started with a triple-digit field since 1966.