The raglan seams are joined by picking up stitches along each edge then binding them off together with a three needle bind off, to create the look of an exposed seam that nicely joins the differing colors on the body and the sleeve. You have the option of simply mattress seaming these stitches instead.

From the designer:
A fresh take on the classic baseball jersey, this top is the perfect spring staple for your wardrobe. Choose your favorite bright color to contrast with a crisp white, or use a solid color for the body and a complementary gradient for the sleeves. Wear the sleeves cuffed or uncuffed, or knit them longer for a three-quarter length.

Shown in size 39”