Jake Arrieta was asked last week if he had any insight into the challenges that await free-agent pitcher Dallas Keuchel once he signs with a team after missing most of spring training. Arrieta, better than most, would know.

It was just last year that Arrieta was the former Cy Young winner who had to wait four weeks into camp before landing a free-agent contract. But before he offered advice, Arrieta offered a plea.

“I would love to have him here,” Arrieta said. “He’d make us better. That’s for sure. No question about it.”

That plea seems likely to go unanswered. A source said this week that the Phillies are unlikely to sign Keuchel, who is still seeking a multi-year contract. Unless Keuchel’s asking price drastically drops, the Phillies will see what they have in Zach Eflin, Nick Pivetta, and Vince Velasquez at the back of their rotation. And if a need arises, the Phillies will be willing to add an arm at the trade deadline.

The Phillies are set to begin the season with the same rotation that stumbled down last season’s final stretch. So what do they have behind Aaron Nola and Arrieta?

Nick Pivetta

Pivetta, among the three pitchers, seems to have the highest ceiling. His fastball is in the mid-90s, his curveball and slider can induce swings-and-misses, and he racked up the 12th-highest strikeout rate last season among all major-league starters.

But Pivetta’s ERA, 4.77, was at least a run more than that of any of the 11 pitchers who topped his 10.33-per-nine-innings strikeout rate.

The Phillies will point to his xFIP, which ranked last season as the 14th best in baseball. The advanced metric, as defined by FanGraphs, measures a pitcher’s expected run prevention independent of the performance of the defense behind him. His xFIP, which the Phillies believe is better than ERA when it comes to predicting success, had a larger discrepancy to his ERA than that of any of the 13 pitchers ranked above him.

So how can Pivetta move closer to that ceiling? He has started this spring by throwing his change-up, which he threw last season for just 65 of his 2,827 pitches. An increase in use of that pitch, which comes from the same grip and arm slot as his four-seam fastball, will provide more life to Pivetta’s fastball, because batters will not be able to sit on his preferred pitch.