SAN DIEGO -- He may be a 23-year-old rookie, but Cristian Javier has emerged as one of the most electric arms on the Astros' pitching staff this postseason. More importantly, he’s one of the most reliable.

As such, manager Dusty Baker waited for just the right moment to deploy his newfound weapon this week. Baker found just the spot Wednesday night, late in Game 4 of the American League Championship Series, with the Astros’ season on the brink.

Javier gobbled up the seventh and eighth innings before allowing a leadoff walk in the ninth. That walk came around to score, and things got tense when closer Ryan Pressly, who had been ready to enter the game in relief of starter Zack Greinke with the bases loaded in the sixth, allowed the tying run to reach third base. But the Astros escaped with a 4-3 victory, cutting the Rays’ ALCS lead to three games to one.

“It was huge, obviously,” Javier said through a team interpreter. “We needed to win today’s game, just like we need to win the ones that are left. We just need to keep the same positive attitude and just take it one game at a time and believe.”

Javier has now tossed 8 1/3 scoreless frames with 11 strikeouts and just four hits this postseason. But he could only watch from the left-center-field bullpen as the Astros dug themselves a 3-0 hole this week. Houston trailed late in all three of those games, and Baker chose to preserve Javier for a situation when his team was ahead.

That moment arrived after six quality frames from Greinke. The Astros led, 4-2. Cool as ever, Javier worked a scoreless seventh, allowing only a soft infield single that caromed off his throwing arm. He shook that off, ending the threat by getting Mike Zunino to pop to first base.

Javier was then tasked with the top of the Tampa Bay order in the eighth, and he breezed through it, 1-2-3, striking out red-hot Rays outfielders Manuel Margot and Randy Arozarena. So effective was Javier that Baker asked for the ninth, albeit with a short leash. When he walked Ji-Man Choi to open the frame, Javier’s ALCS debut was done.

Pressly surrendered a Willy Adames double to the deepest part of Petco Park, and Adames reached third base on a wild pitch. But Yoshi Tsutsugo flied out to end the game.

“We put a lot of pressure on them there right at the end with Willie sitting 90 feet away from tying it,” Rays manager Kevin Cash said. “Yoshi had a good at-bat, got a pitch, it looked like he might have caught it off the end just a little bit.”

When George Springer squeezed the ball in right field, the Astros could exhale, a quarter of the way to their destination. They still face a tall task, needing three wins in three days. But the combined efforts of Javier and Greinke on Wednesday should go a long way toward easing the burden.

“We can’t worry about what we have to do,” Javier said. “We just have to take it one game at a time, come out with the same intensity that we did today, come out tomorrow with our heads up and focus on the job that we need to take care of.”

Baker indicated that he expects Framber Valdez to take the ball in Game 6, if necessary, which would leave Game 7 for Lance McCullers Jr. Considering the way that duo pitched in the first two games, the Astros like their chances.

But first they need to get to a Game 6, and they’ve yet to name a starter for Thursday afternoon.

“Framber has carried a tremendous amount of workload throughout these playoffs,” Baker said. “This is the most innings he's ever pitched. He's such a valuable commodity. We've got to take care of him, and somebody else has to pick up the slack. Then it'll probably be Framber in Game 6.”

Who picks up that slack? That question could define the Astros' season, with Valdez and McCullers waiting in the wings. Baker could go with a bullpen game, or opt to start 23-year-old rookie Luis Garcia, who has all of five appearances and 12 1/3 innings of Major League experience, albeit with an impressive 2.92 ERA.

What about another 23-year-old rookie -- who has met every moment so far this postseason -- for the late innings?

“The bullpen phone rings tomorrow, I’m going to be there, ready,” said Javier, who threw 35 pitches and has never pitched on consecutive days in pro ball at any level. “I’ll be ready to do the same job as I did today, be ready to attack.”