Tim Tebow made his first rookie mistake even before stepping into the batter's box.
The New York Mets newcomer walked behind home plate and took his practice swings near Boston's on-deck circle.
"I didn't know who that was back there. I thought it was the ball boy," AL Cy Young Award winner Rick Porcello said.
The former NFL quarterback's debut as a big leaguer didn't go much better Wednesday.
Tebow went 0 for 3, twice looking at strike three and also grounding into a double play with the bases loaded in a spring training exhibition against the Red Sox.
The 2007 Heisman Trophy winner did safely reach when he was hit by a pitch in the right...