LOS ANGELES -- The Houston Astros' resurgent run through the early part of this postseason was hit with a sobering bit of news Tuesday, following a 5-2 win in Game 2 of the American League Division Series: Right-hander Zack Greinke, the team's most accomplished pitcher by a wide margin, is hurt.

Greinke is dealing with "some soreness in his arm," Astros manager Dusty Baker said shortly after revealing that Jose Urquidy would take the ball opposite Oakland Athletics left-hander Jesus Luzardo in Wednesday's Game 3.

Greinke 36, hasn't completed six innings since Sept. 8 and has a 5.79 ERA over his past four starts. His most recent outing came seven days ago, in Game 1 of the wild-card series, when he gave up one run but recorded only 12 outs against the Minnesota Twins.

"Greinke's ailing some," Baker said. "He didn't say much about it, but it was pretty evident the last three or four starts that he wasn't himself."

Moments after Tuesday's game, which put the Astros one win away from their fourth consecutive trip to the AL Championship Series, Greinke came onto the field while members of the team's taxi squad went through a workout. He threw somewhere in the neighborhood of 15 pitches off flat ground at what appeared to be minimal intensity, then sat on the short fence in right-field foul territory alongside Astros pitching coach Brent Strom. The two engaged in a long conversation before walking off the field together.

If Greinke is out, an Astros team that previously watched Gerrit Cole depart via free agency and lost Justin Verlander to Tommy John surgery could be left scrambling, especially in a seven-game ALCS with no off days within it. If Urquidy can't close out the A's on Wednesday, the rest of this series could get complicated.

"I feel really good," Urquidy, who has been charged with only eight earned runs over his past 30 1/3 innings, said in Spanish. "What happened with Zack is a tough loss for the team, but I feel really good, with no pressure, no nerves, to do a good job tomorrow."