It turns out, there was a reason why Astros manager Dusty Baker wouldn't tip his hand about his Game 3 starter before Tuesday's 5-2 win over the A's in Game 2 of the American League Division Series at Dodger Stadium.

Veteran right-hander Zack Greinke is dealing with arm soreness and is awaiting results after seeing a doctor, so right-hander Jose Urquidy will get the start opposite A's lefty Jesús Luzardo.

Urquidy, 25, was solid when healthy in the regular season, posting a 2.73 ERA in five starts, and he allowed one run over 4 1/3 innings in Game 2 of the AL Wild Card Series against the Twins. Urquidy was saddled with a no-decision, but Houston won that clinching game.

"Greinke is ailing some," Baker said. "He didn't say much about it, but it's pretty evident the last three or four starts that he wasn't himself. Urquidy has been dealing, so it was kind of an easy choice."

Greinke started Game 1 of the AL Wild Card Series on Sept. 29 but was lifted after allowing one run on two hits and three walks in four innings. The 36-year-old faded late in the season, posting a 5.73 ERA over his final seven starts, including giving up at least three runs in each of those outings dating back to Aug. 23.

It's unclear how long Greinke will be out, and Baker did not speculate about the possibility of replacing him on the ALDS roster.

"I can't really say right now," Baker said. "He has some soreness in his arm. He went to see the doctors and we don't have the results yet."

According to Chandler Rome of the Houston Chronicle, Greinke played catch and threw some flat-ground pitches to a catcher with pitching coach Brent Strom watching. After it was over, Greinke was talking with Strom by the outfield wall.

A club may request permission from the Commissioner's Office to replace a player who is injured during the course of a postseason series, but that player is then ineligible for the rest of that round and the subsequent round, if there is one. A pitcher may be replaced only by another pitcher, and a position player only by another position player.

The Astros will instead turn to Urquidy, who didn't make his season debut until Sept. 5 because of undisclosed reasons. He made one start against the A's this year, allowing two runs over six innings in a loss on Sept. 10. Urquidy hasn't surrendered more than two earned runs in any of his outings this year, including the postseason.

Urquidy also pitched well in last year's postseason as a rookie, making three relief appearances and an impressive five-inning scoreless start in a win in Game 4 of the World Series against the Nationals. The Mazatlan, Mexico, native has a career 1.26 ERA in 14 1/3 innings in the postseason and is excited for the chance to start.

"It's a big game for us tomorrow with a chance for us to eliminate them," Urquidy said through an interpreter. "It's a big game for everybody. We've been playing really well. I don't have any nerves."

But the question remains on who the Astros would turn to in a Game 4 if they were to lose, considering Greinke's status. Urquidy, however, said he's not looking beyond Wednesday's start.

"I don't feel any extra pressure," Urquidy said. "I'm just focused on what I have to do tomorrow and what I have to do to be successful."