T. Grodnick was a Starfleet officer in the 23rd century.

In 2285, he was a lieutenant commander at Starfleet Academy's Starfleet Training Command. He was an Astrogation instructor. His office, located on the second level of a building, was in room #206. His rank, name, position, and office were listed on a directory placard. (Star Trek II: The Wrath of Khan, set artwork)

This character was only mentioned in writing.
He was named after assistant director Todd Grodnick. The placard was sold on It's A Wrap! sale and auction for US$31.99. [1]