Zach Eflin can’t say for sure when he will pitch again, an uneasy predicament for the Phillies regardless of the time of year.

With two days until the trade deadline, it’s even more problematic.

Eflin went on the injured list July 20 with patellar tendinitis in his right knee. At the time, neither the Phillies’ No. 3 starter nor manager Joe Girardi said he was concerned about a prolonged absence. Last Saturday, president of baseball operations Dave Dombrowski joined the chorus, saying the Phillies “think Eflin is going to be fine.”

But then came a bullpen session last Sunday and lingering discomfort in Eflin’s knee. Rather than reinstating him from the injured list after the minimum 10-day term, the Phillies announced he wasn’t ready to come back. Eflin’s status hasn’t changed.

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“We’re just going day to day and doing everything we can to strengthen the areas around the knee,” Eflin said Wednesday before the Phillies-Nationals game at Citizens Bank Park was postponed because 12 members of Washington’s traveling party tested positive for COVID-19. “Ultimately it’s a day-to-day thing, and I’m pretty much letting my body do the talking.”

The Phillies were already hunting for a back-end starter to replace struggling Vince Velasquez and deepen the rotation. But with Eflin suddenly looking like a 6-foot-6 question mark, finding another starter has become a heightened priority.

It appeared the Phillies made a trade Tuesday for Tyler Anderson, an innings-eating left-hander whose modest salary ($2.5 million) would’ve enabled them to pick up a low-cost setup man or two (the Cubs’ Ryan Tepera or Miami Marlins’ Dylan Floro, for instance) and still stay under the $210 million luxury-tax threshold. But the deal fell through when the Pittsburgh Pirates raised concerns about single-A pitcher Cristian Hernandez’s medical report and instead sent Anderson to the Seattle Mariners in a trade that was completed late Tuesday night.

There are alternatives to Anderson, a rent-a-starter who will be a free agent at season’s end. The Phillies could pick up the Colorado Rockies’ Jon Gray (3.67 ERA in 18 starts) or the Chicago Cubs’ Zach Davies (4.30 ERA in 21 starts), probably for a similar combination of players in the low minors.

But the Phillies’ best path to a division title in the middling NL East includes a healthy Eflin.

Even with unappealing fourth- and fifth-starter options, uncertainty at the back of the bullpen, and an offense that comes and goes, the Phillies would have a chance if Zack Wheeler, Aaron Nola, and Eflin could start at least 36 of the final 62 games. Each topped 100 innings before the All-Star break, and they have combined for a 3.56 ERA in 58 starts.

Now, with Eflin, all bets are off.

“I don’t know if there’s a timetable for any of it,” said Eflin, who has a 4.17 ERA and a 99-to-16 strikeouts-to-walks ratio in 105 2/3 innings. “I could show up tomorrow and be great and try to throw a bullpen as soon as possible and go from there. It really all depends on how the body reacts to everything.”

» READ MORE: Phillies' trade for starter Tyler Anderson falls through; Pirates deal lefty to Mariners instead

Eflin, who underwent surgery on both knees in 2016, played catch Wednesday but hasn’t gotten back on a mound since Sunday. He doesn’t have another bullpen session scheduled yet. He’s taking anti-inflammatory medication and receiving treatment from the athletic training staff.

The Phillies will be extra cautious because of Eflin’s history of knee trouble. They want be to sure he doesn’t change his mechanics to compensate for knee pain and wind up injuring his arm. The injury is affecting his push-off leg, which also could prevent him from generating power.

“That’s where all the torque and everything comes from,” Eflin said. “We’re just trying to get that to calm down so I get back into the drive, and everything else will flow from that.

“Some days have been better than others. Just right now it’s kind of barking every day.”

In Eflin’s stead, the Phillies are hoping to get quality innings from enigmatic prospect Spencer Howard. He started last week on short rest and tossed three scoreless innings at Yankee Stadium. They were hoping he go pitch deeper into Monday’s game against the Nationals, but he left in the fourth inning when a callus formed over a blister on his right hand.

Howard threw a bullpen session Wednesday without a problem and is scheduled to make his next start Saturday night in Pittsburgh.

But Howard, Velasquez, and Matt Moore, all of whom are presently in the rotation behind Wheeler and Nola, have combined for a 5.79 ERA in 32 starts. Velasquez, in particular, has struggled with a 7.74 ERA in his last 10 starts. He hasn’t gone past the third inning in two of his last three starts.

It’s little wonder Phillies officials are said to be burning through their phone batteries in search of pitching help.

“You can always use starters, of course,” Bryce Harper said. “I’ve always said my whole career, pitching and defense wins. Timely hitting, of course, but pitching and defense will always be king in this game.”

» READ MORE: Mickey Moniak has been hot at the plate. Is he in the Phillies’ plans or a trade candidate?

Extra bases

Outfielder Travis Jankowski rejoined the team after being cleared to return from the COVID-19 restricted list but has not been activated because he’s trying to regain weight that he lost while he was sick. Jankowski didn’t test positive for COVID-19 but was placed on the list as a precaution. ... Wheeler (8-5, 2.37 ERA) and Velasquez (3-5, 5.54) are scheduled to start Thursday, but it was unclear who will start which games.