This is the guy that Joel Hornick talks to Jerry about at Monk's coffee shop right as Jerry is trying to "break up" with him. This is in the "Male Unbonding" episode.
JOEL: Wait, you'll never guess who I ran into.
JERRY AND JOEL: Howard metro.
JOEL: He asked me if I still saw you. I said, "Sure, I see him all the time. We're great friends." Anyway, Howard says hello.