Not surprisingly, Jake Arrieta is set up to start the NL wild-card game the Chicago Cubs appear to be headed toward.

In the meantime, the right-hander will try to become the first Cub in 43 years to win an eighth consecutive start in Friday night's doubleheader against the Philadelphia Phillies at Citizens Bank Park.

For the first time publicly, manager Joe Maddon said this week that Arrieta (18-6, 2.03 ERA) is in line to take the ball in a potential wild-card matchup next month instead of seasoned playoff veteran Jon Lester. While Chicago (80-58) is seven games behind St. Louis for the NL Central lead, it has a firm grasp on the second wild-card spot and is 2 1/2 games behind Pittsburgh for the top position.

More from FoxSports

"He's the best pitcher on this team right now; he's probably the best pitcher in the league right now," Lester told MLB's official website.

The Cubs have won eight straight starts by Arrieta, the major league leader in victories. He's won the last seven while yielding two earned runs in 50 1-3 innings, holding opposing batters to a .133 average with 50 strikeouts and 10 walks.

Arrieta was scheduled to start Thursday's series opener before it was postponed due to rain. Now he'll get the ball in Game 1 on Friday with a chance to become the first Cub to win eight consecutive starts since Milt Pappas' 11-game run in 1972.

Arrieta followed up his no-hitter at Dodger Stadium by yielding four hits, fanning seven and not walking a batter in eight innings of Saturday's 2-0 victory over Arizona. Building his case for the NL Cy Young Award, he's gone 29 innings without allowing an earned run.

"It's hard for me to fathom that somebody is better than Jake Arrieta," catcher David Ross said. "I know numbers are numbers, and there are some guys in L.A. that are doing a really good job, but I'll take that guy on the mound any day of the week."

The only team to beat him over the past 2 1/2 months is the one he'll face Friday. All three runs Arrieta allowed in six innings came on a homer by Ryan Howard in a 5-0 defeat to Philadelphia on July 25 - the day Cole Hamels no-hit the Cubs.

Since being swept by the Phillies in that three-game set, Chicago is 29-12. However, the Cubs had a five-game winning streak snapped Wednesday when they blew a late two-run lead in a 4-3 loss at St. Louis.

Kyle Hendricks (6-6, 4.08) seeks his first win in six starts in the nightcap when he faces Philadelphia for the first time. The right-hander has a 5.48 ERA over his last nine, though he allowed just one run and three hits over five innings in Monday's 6-4 home win over Arizona.

While the Cubs are thinking about the playoffs, the MLB-worst Phillies (54-86) will miss the postseason for the fourth straight year and have decided to make a change in management.

President-in-waiting Andy MacPhail announced that general manager Ruben Amaro Jr. was fired Thursday, naming assistant GM Scott Proefrock as his replacement on an interim basis.

"We needed a fresh perspective, a fresh approach," MacPhail said.

The Phillies have lost 12 of 16 after Wednesday's 8-1 defeat to Atlanta, and Howard enters in an 0-for-27 drought.

Adam Morgan (5-5, 4.42) starts the opener looking to bounce back after allowing six runs in 6 1-3 innings of a 7-5 loss at Boston on Friday.

"It's all about having a short memory," the rookie left-hander said.

Morgan could face Starlin Castro, who no longer is an everyday player but is 7 for 12 in his last four contests - including 4 for 5 off southpaws. He's hit .355 in 16 career games at Philadelphia.

Rookie right-hander Alec Asher (0-2, 10.61), acquired from Texas in the Cole Hamels trade, seeks better results in Game 2 after giving up seven runs over 3 1-3 innings in Saturday's 9-2 loss at Boston.