MLB's Ryan Zimmerman Plays Goalie For Capitals, Saves Ovechkin Slapshot!

Here's something that'll make you feel REALLY unathletic ... Nationals star Ryan Zimmerman suited up in goal for the Capitals on Wednesday -- and saved an Alex Ovechkin slap shot!!!

Unclear why the Washington infielder decided to trade in the mitt for a set of goalie pads this week ... but he sure as hell impressed everyone watching at Caps practice.

Zimmerman got between the pipes and stopped one-timers from Ovi ... and later got in some shootout drills, where he didn't suck either!

But, the most impressive part? That came when Alex decided to fire a missile at Zimmerman from the point -- and he saved it with a flashy piece of leather!!!!

Zimm was pretty humble after the workout ... hilariously calling it all, "terrifying."

"What a great experience," he said. "Terrifying, but fun. Glad I did it, but I'll never do it again."