But there's nothing wrong with his feet. Assuming the elbow heals in another day or so as expected, he can resume showing the nimbleness that could give him a real chance in the competition for the start at second.
It's something Baker, 26, a corner infielder-outfielder who was the primary right-handed pinch-hitter last season, has worked toward since meeting with general manager Dan O'Dowd late last season. Prospect Jayson Nix and non-roster veteran Marcus Giles are natural second basemen and logical candidates to replace 2007 second baseman Kazuo Matsui, now with the Astros.
Omar Quintanilla, Clint Barmes and Ian Stewart are candidates. Like Baker, Stewart is a natural third baseman. Baker is looking more like a second baseman than a third baseman looking for a chance.
"After Dan had a meeting with me to talk about possibly moving to second, during BP and stuff I tried to get as many ground balls and take as many fungoes as I could at second," Baker said. "And I just watched Matsui and Jamey Carroll, and then working with 'Gags' [third base coach Mike Gallego] and Walt Weiss [a special front-office assistant], I kind of had a good pace and fundamentals to go back to the offseason with. I just touched base with Gags this offseason, and he'd offer some tidbits here and there."
Gallego said he passed to Baker borrowed ideas from boxing.
"I suggested he start jumping rope," said Gallego, who referred to Baker as a 'B' student -- a high grade for a player who hasn't played the position in a Major League game. "That was something I did as a player. Another thing I told him to do was start hitting off the speed bag. I basically told him he could work out as a boxer.
"Whether he did, I don't know. But whatever he did, he's quickened up his feet and hands. When your feet are working, your hands come. He's done extra homework."
Baker said he never got around to the speed bag, but said he picked up the intensity of the rope jumping and it helped.
Continuing with the boxing theme, Baker is making his second drop in weight class in as many years. Last year, Baker, a third baseman by trade who has weighed as much as 225, dropped to 210-215 while adding outfield to his duties. This year, he's 205.
The lighter body worked well at second on Thursday against the Diamondbacks, especially while turning an eighth-inning double play with a runner bearing down on him. Also, manager Clint Hurdle has noticed that the drop in weight has had little or no effect on his bat speed.
"It's one of those fun things, to kind of seeing my body transform to what it needs to be," Baker said. "I went into college really skinny at 175 and came out 215. So maybe next year I'll be 245 and be jacked. I don't know.
"I was able to cut down some body fat and issues like that and maintain my strength, but at the same time gain some lateral quickness. So it was definitely something that was good. I'm probably close to as strong as I have been in the past, but not quite."
Baker, who also has seen time at first base, said he is still learning how to handle bunt plays and rundowns, since at second base he'd be essentially doing the opposite of what a corner player would do. But it's becoming more natural.
Several freak injuries slowed Baker's progress through the Minors. For example, he suffered a concussion when hit by a throw when he was trying to score, and a thumb injury when he was hit with a line drive during batting practice.
As for the elbow injury, he was hit by Diamondbacks right-hander Jailen Peguero to force in the run that turned a possible loss into a 5-5 tie. Baker's response to the suggestion that he took one for the team was a pained, "Ugh."
But once the injury heals, Baker will continue his fight for second base.
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.