PHILADELPHIA -- Alek Manoah has had trouble finishing off batters after getting to a two-strike count in 2023. He's also struggled with his overall command -- as a result, he's been unable to pitch deep into most games.

But it all stems from his slider.

Manoah once again struggled to command that key offering in Tuesday night's 8-4 loss to the Phillies at Citizens Bank Park. Not only did Manoah fail to register a single swing and miss with his slider, but Philadelphia right fielder Nick Castellanos clubbed a two-run homer on a 2-2 slider that Manoah left over the plate in the fourth inning.

“Just trying to be perfect; my stuff's good enough,” said Manoah, who fell to 1-3 with a 4.83 ERA through eight starts. “I really don't need to be trying to paint corners or anything -- I just need to get back to attacking hitters with my best stuff and make them come beat me. Right now, I'm beating myself a little bit.”

Manoah's problems start with the slider, but they snowball from there.

Last season, Manoah induced a 31.8% whiff rate with his slider -- his highest for any pitch. So without a good feel for one of his go-to swing-and-miss pitches, Manoah hasn't been able to get opposing hitters to bite on anything outside of the zone.

Case in point: Manoah threw 30 sliders on Tuesday night. The Phillies laid off 15 of them for balls. They swung at 13 of the other 15 and made contact all 13 times (eight foul balls, five balls in play). Just two went for called strikes.

“When a team can eliminate a pitch, it makes it really tough to put guys away,” manager John Schneider said. “When that [slider] does come back into play, he's going to be just fine.”

But without needing to worry about the slider, Philadelphia whiffed on just three of its 42 swings (7.1%) against Manoah on Tuesday night. That came after the Red Sox missed on only three of their 45 swings (6.7%) against Manoah last Wednesday at Fenway Park.

Those are the second- and third-worst whiff percentages of Manoah's 59 career starts.

“I really can't control what hitters do once I throw the ball,” Manoah said. “So yeah, the whiffs aren't there, but I feel like I've just got to keep making pitches. I really can't do much once the ball leaves my hands.”

Along those lines, Manoah certainly doesn't need to rack up big strikeout totals to have success. He did not have a double-digit-strikeout game in any of his 31 starts last season on his way to posting a 2.24 ERA and finishing third in AL Cy Young voting.

What Manoah did in 2022, however, was finish off batters once he got to two strikes.

Opposing hitters slashed just .139/.199/.211 with two strikes against Manoah last season. They are slashing .253/.340/.396 in two-strike counts this year.

That includes the Phillies going 3-for-10 with four walks against Manoah in those situations on Tuesday. In other words, Manoah allowed batters to reach safely in half of his two-strike counts, including Castellanos' fourth-inning homer and Trea Turner's fifth-inning RBI single -- on an 0-2 fastball over the middle of the plate -- that ended Manoah's night.

Manoah has been unable to complete five innings in half of his eight starts this season. He pitched at least five frames in all 31 starts last year -- and completed six innings in all but six of them.

But with the Phillies fouling off 21 pitches and working four walks, Manoah needed 94 pitches (59 strikes) just to navigate 4 2/3 innings.

“I feel like I threw about seven pitches to every hitter, but I just tried to compete as much as I could,” Manoah said. “I feel like they did a good job of extending at-bats and not swinging at some of the chase pitches. That's why I was only able to go 4 2/3.”

Though Manoah has struggled in multiple areas -- two-strike approach, command and missing bats -- this season, the Blue Jays are confident all of it will fall into place as soon as Manoah does one thing: unlock his slider.

“Alek is really good for a reason and he's going to fix it,” Schneider said. “I think when you look up at the end of the year, this will be a blip on the radar -- a little bit of a speed bump. … We have all the confidence in the world in him.”