The New York Mets, who dropped a three-game series at Philadelphia last week, will look to clinch a three-game series with the visiting Phillies on Tuesday.
Both teams are 12-10, including a 2-2 mark in head-to-head matchups.
Wheeler (1-2, 6.35 ERA) has steadily improved this season.
The 28-year-old Georgia native has tossed consecutive quality starts. In his most recent outing, Wheeler gave up three runs in seven solid innings during a 3-2 loss to the Phillies on Wednesday. He was touched for solo homers by Scott Kingery and Cesar Hernandez.
"I think those are just two mistakes that cost me and cost the team a win, and other that, I did well," Wheeler said. "I definitely need to cut down on the walks. Those have been killing me so far this year. I just needed to attack the zone early and get ahead."
Wheeler has had success against the Phillies in his career, going 4-2 with a 3.67 ERA in 11 starts.
Eflin (2-2, 3.68 ERA) also took a hard-luck loss last week. In six innings against the Rockies on Thursday, he allowed three runs (two earned) in six innings. He primary blemish was a three-run homer he served up to Ryan McMahon.
"I'm not disappointed with the way I pitched," Eflin he reporters after the outing. "It was one moment."
Eflin has allowed two or fewer earned runs in three of his four starts this year. He is 2-3 with a 5.25 ERA in seven career starts against Philadelphia.
It is unclear if Eflin will be facing the Mets' hottest hitter, Jeff McNeil. The infielder/outfielder stayed red hot Monday with a solo homer and a single to increase his average to .384. However, he was also hit in the hand by a Jose Alvarez pitch. Postgame X-rays reportedly were negative, but McNeil's status for Tuesday was uncertain.
McNeil has crushed the Phillies in his career, going 28-for-58 (.483) in 15 career games.
The Mets also received a lift Monday from third baseman Todd Frazier, who went 1-for-4 in his season debut after missing the first 21 games due to a strained left oblique.
The struggling Phillies dropped three of four at Colorado last weekend, then looked flat in the series-opening loss to the Mets.
Over the last five games, the Phillies are 7-for-39 with runners in scoring position.
In the Monday contest, which started 95 minutes late due to a rain delay, the final 16 Phillies batters were retired.
"I don't think anybody is hitting the panic button," first baseman Rhys Hoskins told reporters after hitting a solo homer for the team's lone run. "We've been pretty good at bouncing back."
The patchwork Phillies lineup managed only three hits on Monday, two by Hernandez. Shortstop Jean Segura, center fielder Odubel Herrera and Kingery all went on the injured list in the past week due to a hamstring ailments.
"We didn't swing the bats the way we're capable of swinging the bats," Philadelphia manager Gabe Kapler said after the game Monday.
--Field Level Media