Next up will be a Minor League game Tuesday at Fitch Park, and if all goes well, Baker's next step would be a Cactus League game.
"He's feeling good today and everything's going really well," Cubs manager Dale Sveum said. "Barring no setbacks, he's perfectly right on schedule that we planned out from the beginning."
The radar guns showed Baker hitting about 89 mph during his second inning of a two-inning workout Thursday.
"I'm starting to feel more comfortable with my mechanics, which allows me to put forth more effort," Baker said. "Now that I feel like I'm doing that, the only way to throw harder and to gain that arm strength is to pitch. I feel like that's the point I'm at, is the day after is an important day, and today, I feel great. Now that I can get back on a normal five-day rotation is even more of a benefit for me."
He had been throwing every third day to build up his arm. Now he's back on a normal starting pitcher's routine.
"I'm excited," Baker said about his progress. "I didn't get to see the velocity readings yesterday, but I was happy with what they were telling me. Of course, we're talking about a simulated game on the back field, so there's not as much adrenaline there, obviously, as in a game. At the same time, that's something you have to take into consideration. You have to be cautious and mindful of that intensity."
Matt Garza, sidelined with a strained lat, also is improving, and may play catch Sunday or Monday, depending on how he feels.
The Cubs have enough depth with their starting pitching to give Baker and Garza time to heal completely. Once the two come back, they'll be in even better shape. Neither was expected in the first month of the regular season.
"If he comes back like the Baker we saw in Minnesota before he got hurt and Garza comes back about the same time, you're looking at a pretty good starting pitching staff at that point, if everyone is pitching up to their capabilities," Sveum said.
Their return would mean pitchers like Carlos Villanueva would switch from the rotation to the bullpen, but that will only help out the relievers.
"It solidifies the whole staff," Sveum said.