Toronto manager Cito Gaston thinks Ricky Romero is a much improved pitcher now that he has some experience.

The 25-year-old left-hander pitched three shutout innings, allowing four hits and striking out two, in the Blue Jays' 4-1 win over the Houston Astros in Kissimmee, Fla., on Monday.

Romero went 13-9 in 29 starts as a rookie last season. He strained an oblique muscle and missed 24 games early in the year but still pitched 178 innings, second on the team to ace Roy Halladay. With Halladay traded to Philadelphia, the more mature Romero could be the front-runner to take over the No. 1 spot in the rotation.

"He's got experience," Gaston said. "It doesn't matter who you are, you're going to be a little bit nervous when you're pitching in the big leagues for the first time or playing or going up to this.

"Now's he's got some experience behind him. He's been successful and he just gets better all the time."

J.P. Arencibia hit a solo homer off Houston starter Bud Norris in the first inning, and Lyle Overbay and Brad Emaus had run-scoring doubles off left-handed reliever Tim Byrdak for Toronto.

Norris, expected to fill the No. 4 spot in the Astros' rotation, allowed two hits and struck out two in two innings in his first start of the spring.

"You're just trying to get the cobwebs out," Norris said. "I've been doing this for a few years.

"I know what I'm doing pitching, and you just keep going through your routine. You're just trying to get your routine back in order."

John McDonald drove in a run with a single in the sixth off Houston lefty Gustavo Chacin. Houston's J.R. Towles, trying to win the starting role at catcher, drove in the Astros' lone run in the eighth off Chad Jenkins.

Romero allowed 79 walks in 2009, second in the American League. He hasn't allowed a single walk in two starts and five total innings this spring.

"He didn't throw a lot of balls, period," Gaston said of Monday's outing. "He just went out and pitched well here again."

'They threw the ball real well'

Towles accounted for three of Houston's seven hits. The Astros averaged more than seven runs in their first four spring games before Romero and Dana Eveland limited them to five hits through six scoreless innings.

"You'd like to see us be able to string some things together," Houston manager Brad Mills said. "Their two left-handers — Romero and Eveland — they kind of shut us down a little bit.

"They threw the ball real well."

Zach Stewart pitched a scoreless ninth for Toronto to earn his first save of the spring.