Jason Vander Laan isn't just a rookie undrafted free agent adjusting to the NFL. He's a rookie free agent adjusting to the NFL while also learning an entirely new position.
Vander Laan had a decorated college career at Ferris State. He twice won the Harlon Hill Trophy, which is the Division II equivalent of the Heisman Trophy. He's college football's all-time leader in rushing yards (5.953) and by a quarterback (5,953). He's the first player in NCAA history to run and pass for 1,000 yards for four straight seasons.
And the Jets signed him just after the draft to be a tight end.