The New York Mets rested their young ace ahead of the All-Star game.
The Pittsburgh Pirates didn't have a choice in skipping Jeff Locke.
With Locke sidelined due to a back injury, the Pirates will turn to rookie Gerrit Cole as they try to enter the All-Star break with their longest winning streak over the New York Mets in 21 years Sunday.
The Mets (40-50) opted to skip Matt Harvey's turn in the rotation, making him available to pitch - and potentially start - Tuesday's All-Star game at Citi Field.
The Pirates (56-36) aren't afforded the same luxury. Locke will miss his scheduled start Sunday and is out of the Midsummer Classic thanks to discomfort in his back suffered during Monday's 2-1 loss to Oakland.
The left-hander is 8-2 and his 2.15 ERA is second in the majors behind the Los Angeles Dodgers' Clayton Kershaw (1.98).
"The only thing I'm disappointed about is not being able to go (Sunday)," Locke said. "It's not one of those things where I can't go (Sunday) but I can go in the All-Star game. I think it'd be disrespectful to the team. I don't think it's even questionable ... I'll just go there and enjoy it and come back after the break."
Now, Cole (4-2, 3.68 ERA) will fill in for Locke and try to help Pittsburgh to its first six-game win streak against the Mets since a seven-game run in 1992.
The Pirates are tied with St. Louis atop the NL Central, and already assured of their best record at the break since 1975 after rallying for a 4-2 win over New York on Saturday.
"We just want to continue to keep rolling," center fielder Andrew McCutchen said.
Cole, though, is 0-2 with a 3.65 ERA in two starts this month. The only runs the 22-year-old right-hander gave up Tuesday over a season-best seven innings came on a two-run homer by Oakland's Brandon Moss in a 2-1 loss.
McCutchen, one of four Pirates named to the All-Star team, is batting .392 over the past 14 games after hitting a solo homer before connecting for a go-ahead single in the seventh Saturday.
The star center fielder has a .362 average in 14 career home games against New York.
After skipping Harvey's scheduled start Saturday, the Mets are expected to turn to Dillon Gee (6-7, 4.60), who is 2-0 with a 1.73 ERA in four career starts versus the Pirates.
The right-hander limited them to one run over five innings at Citi Field on May 9, but hit two batters and threw 101 pitches before departing in the Mets' 3-2 walkoff win.
Gee earned an 8-1 victory in his only visit to Pittsburgh on June 10, 2011, yielding one run and eight hits in eight innings.
He wasn't nearly that sharp Tuesday at San Francisco, surrendering five runs and a season-high five walks in 6 2-3 innings while not getting a decision in a 10-6 win.
Mets' All-Star David Wright went 0 for 5 with two strikeouts Saturday to end his 12-game hitting streak.