PITTSBURGH -- Blasting the competition in the National League West while threatening the major league record for wins in a season did not sidetrack the Los Angeles Dodgers from acquiring right-handed ace Yu Darvish from the Texas Rangers at the trade deadline.

It's all about the postseason for the Dodgers, who have not won a World Series since 1988. Winning it all is the only acceptable outcome for the club and its fans.

Darvish, however, will not take the mound as scheduled Tuesday against the Pittsburgh Pirates in Game 2 of a four-game set at PNC Park. Pitching on his 31st birthday in his home debut Wednesday against the Chicago White Sox, Darvish experienced tightness in his back and left after six innings.

The injury appears to be minor, but the club won't take an unneeded risk with Darvish, who won his first two starts for Los Angeles, striking out 10 in both games. After he got a no-decision Wednesday vs. the White Sox, Darvish said manager Dave Roberts told him, "Let's play it safe."

The missed start Tuesday is considered a precaution.

No replacement for Darvish was officially announced, but Roberts on Monday said rookie left-hander Brock Stewart would get the ball "unless something unforeseen happens."

Although he has pitched mainly in the minors this year (he would be summoned from Triple-A Oklahoma City to start Tuesday), Stewart started twice for the big club in late July and early August with mixed results.

He yielded seven runs in 7 2/3 innings in his two starts, but only two of the runs were earned.

Stewart is 0-0 with a 1.64 ERA in 22 innings over nine big league appearances for Los Angeles in 2017. Last season with the Dodgers, Stewart was 2-2 with a 5.79 ERA in seven appearances (including five starts).

He is 0-0 with a 3.00 ERA in one career appearance against the Pirates, which came last year when he gave up two hits and a run in three innings.

Asked what he expects from Stewart, Roberts said, "Just attack the strike zone. He's got a plus fastball. He's got a plus change and a good slider. It's just filling up that strike zone."

The Pirates will start right-hander Jameson Taillon (7-5, 4.64 ERA). He is 0-0 with a 9.00 ERA in one career start against the Dodgers, and that took place last year when he gave up eight hits and four runs in four innings.

In addition to Darvish, rookie sensation Cody Bellinger likely won't play Tuesday, Roberts said. The outfielder sprained his right ankle Sunday against Detroit and did not play Monday.

The Dodgers also are without left-hander Clayton Kershaw, perhaps the game's top pitcher, who has missed a month with a lower back strain. There have been other injuries, but the club has shrugged off all negative issues as it assaults the major league record of 116 wins shared by the 1906 Chicago Cubs and the 2001 Seattle Mariners.

On Monday, Los Angeles fell behind the Pirates 3-0 after three innings, rallied to take a 5-3 lead, saw that slip away, yet still won 6-5 in 12 innings.

Citing the injuries and the additions, as well as the blossoming of such players as Bellinger and left-hander Alex Wood, the "transition" of the Dodgers' 25-man roster has been fun to watch, Pirates manager Clint Hurdle said.

"The active roster has really complemented each other, from starting pitching to bullpen," Hurdle said. "Offensively, they have a dynamic lineup. It's just been a nice roll."