Alonso immediately clutched his arm.
"Not good," said Padres manager Bud Black. "You think worst-case scenario. It looked like it might be a shoulder issue. But when I went out there, he said it was his elbow."
After working for a few minutes with trainer Paul Navarro, who quickly put Alonso through a handful of strength tests to determine if there was an injury, Alonso's pain started to subside. He ended up staying in the game and was in the starting lineup on Thursday.
"I woke up today and it was good," Alonso said. "I was a little scared for a second. But when Paulie went out and started playing with it, I knew it would be fine."
The Padres are already without third baseman Chase Headley for what will likely be most of April, if not longer, while infielder Logan Forsythe is sidelined indefinitely with plantar fasciitis in his right foot. Two other players -- pitcher Casey Kelly and Minor League outfielder Rymer Liriano -- needed reconstructive elbow surgery in Spring Training.
The last thing the Padres needed was another significant injury. That's why Black felt the team dodged a bullet Wednesday.
"Those things don't look good when they happen," Black said.
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.