Lyon, Houston's biggest offseason acquisition who signed a three-year, $15 million contract in December, has yet to pitch in a game this spring after having a cyst drained in his right shoulder in January. He threw 25 pitchers to hitters and worked in his complete arsenal.
Heavy rains pounded central Florida for the second consecutive day, forcing Lyon to pitch inside a batting cage instead of on the mound on a field.
"It's hard to judge on something like this, especially when you're doing BP and [the hitters] know it's coming," he said. "The weather obviously is not cooperating that well. I'd like to get outside and feel like a game situation, but as far as the way my arm felt, everything felt good, and I think it's another stepping stone."
Astros pitching coach Brad Arnsberg was also encouraged.
"[Lyon] came in feeling good," he said. "He gave good effort and all of his pitches are pretty tight. He threw a couple of sliders and got underneath them, but he stayed with his mechanics real well and he's downhill and he looks healthy. We'll see he feels in the morning. That's always the telltale sign. But his velocity was pretty good and he gave good effort."
The Astros were rained out Friday in Dunedin, Fla., but the pitchers scheduled to throw in that game, including starter Brian Moehler, got their work done by throwing in the batting cage once the team returned to Kissimmee.
"We'll get the guys throwing so we can keep on track and keep everybody moving," manager Brad Mills said.
Lyon threw three 30-pitch bullpen sessions earlier this week as he tries to get his arm strength back to game shape.
"It's a different reaction than being out there on the fields or the whole surroundings," he said. "The progressive steps we take in Spring Training, we start bullpens and go out and throw batting practice and then we get in a game. I don't really know how to judge it right now, except for my arm felt good."
Lyon threw fastballs, changeups, curveballs and sliders to the hitters, some of whom were simply standing in the box and some of whom were swinging.
"I started working everything in, and by the end I was jerking a little bit and out of my mechanics so I just kind of stuck to my fastball, trying to locate it," Lyon said. "For the most part, my arm felt pretty decent."
As has been the case each time he throws, Lyon says the health of his arm will dictate what comes next. He hasn't had any setbacks in any of his throwing sessions, and if all goes well he'd like to get back on the mound by the end of the weekend.
"We have that off-day on Monday,, so I'd like to do something again Sunday against some hitters, so we'll see how I react [Saturday]," he said. "I say that every time and it feels good, and I'm hoping for the same and to be able to do something again Sunday. I'm probably going to take [Saturday] off and do some long toss in my throwing program, and then do something Sunday against some hitters."
Lyon, who could be the team's closer on Opening Day, went 6-5 with a 2.86 ERA in 65 games last year with Detroit and saved 26 games for Arizona in 2008.
Brian McTaggart is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.