I made a shirt with baseball sleeves and had my camera nearby, so I made a tutorial. OMG. Hahaha... I am showing the secret of how I make sleeves! AHHH!
For a baseball tee, cut the sleeves off at an angle to the neck.
Cut the seam on the underside of the sleeve so it opens flat, and cut out one like it from whatever material you're using. Baseball sleeves are usually a little longer than tee sleeves, so remember that.
Groovy. This is how your shirt is gonna (sorta) look. Now cut up the sides of the teeshirt, like up to the armpits...
and open the shirt out and lay it flat. Lay the sleeve peices out flat too. Sew the pointy end of the sleeve peice against the collar, and then the side bits along the armpitty part of the shirt. I might have to make an illustration for that because it doesn't really make sense... haha. Now you'll have this cross-shaped peice. Turn it inside out and do up the underarm seams and side seams of the shirt... and voila! Baseball tee.
Mine was kinda boring, and this was a shirt for my first day of school tommorow so I scribbled on it with markers. It's a line of Vendetta's from Making Fiends, which you ALL should check out. www.makingfiends.com
And the back, which is Vendetta herself. Hahahah.