Warren went 3-1 with a 4.56 ERA in 25 relief appearances before being sent to Triple-A Iowa to make two starts and get stretched out. He threw 73 pitches over five innings in his last start on Thursday at Round Rock.
Last season with the Yankees, Warren was 6-6 with a 3.66 ERA in 17 starts and 1-1 with a 2.29 ERA in 26 relief appearances.
"I do take pride in being able to do both," Warren said.
The Cubs were still debating whether to have Warren continue in the rotation after the break.
"I'll have the opportunity to prove myself," Warren said of Wednesday's game against the Reds. "If they ever need another guy, I want to put my name at the top of the list."
• All nine players in Monday's Cubs lineup were age 26 or younger, which the team hasn't had done since Oct. 1, 1964.
"You write it down on paper, that's one thing," Cubs manager Joe Maddon said, "then you watch them run out to their positions, and that's really unusual. That's sustainable for years. ... You like them now, that's great. They're going to get better."
The future is bright for the Cubs.
"It says a lot about what they've been doing here for the past five years, gathering talent and young talent and developing them," Kris Bryant said. "It says a lot about the future and how good we can possibly be."
• Maddon managed the American League All-Stars in 2009 after leading the Rays to the World Series the previous year. Having the All-Star Game count for more than just an exhibition influenced his pregame planning. The AL had won the event 11 straight years at that point, not including the tie game in 2002.
"I did not want to be the manager who lost the first game in, maybe, 10 years," Maddon said.
He remembers the event well, especially his pregame address.
"I'm looking at this audience of the best baseball players in the world," Maddon said. "The president says, 'Hi.' It's kind of like World Series week in one day. I like that our All-Star Game stands out in regard to the matter that it does matter. I think the other ones are pretty much showcases, which is cool."
Ben Zobrist wasn't a big fan of having the All-Star Game determine home-field advantage for the World Series.
"I wish it was just the team that gets to the World Series, I wish it was just that team's play that gave them home-field advantage,' Zobrist said.
• Bryant hit his 24th home run on Monday, and the 50th of his career. He's the fastest Cubs player to hit 50, doing so in his 867th career at-bat and topping Ernie Banks, who hit his 50th in his 889th career at-bat on Aug. 10, 1955.