Outwardly, the Phillies feel they have a good amount of starting pitching depth with Jerad Eickhoff, Cole Irvin, Vince Velasquez and Nick Pivetta all potential options as the Nos. 4 and 5 starters.
But how confident can they really be in any of the four of them on a start-by-start basis?
Eickhoff, who faces a tough Brewers team tonight, has experienced predictable regression in his last two starts, allowing five homers and nine runs in nine innings after pitching to a 1.50 ERA and not allowing a home run in his first 30 innings.
Irvin was optioned to Triple A after allowing seven runs in 4⅔ innings on Wednesday night. The degree of difficulty in that start was high - good Cubs team, on the road, with the wind blowing out at Wrigley Field. Irvin's demotion seems less about the Phils closing the book on him and more about them looking to utilize an extra reliever until that turn in the rotation comes up again. Regular rest would have had Irvin start on Monday, but the Phillies are off, meaning they could go with a four-man rotation until June 1.
The Phillies have designs of playing well into October, and it's just hard to believe they have enough starting pitching, even if you have a rosy outlook for guys like Pivetta and Velasquez upon their returns.
Fortunately for the Phils, their top need aligns with what this summer's trade market offers - in both quality and quantity.
Philadelphia Phillies
Complete coverage of the Fightin' Phils and their MLB rivals from NBC Sports Philadelphia.
If the Phillies want to go after a top-of-the-rotation rental, that pitcher will be available.
If they want a cheaper solution, that exists too.
If the preference is a pitcher who would cost you more in money than in prospects, one of those could be had as well.
Zack Greinke
Greinke fits that last description. He has about $20 million remaining in salary this year and $64 million total the next two seasons. However, $32M of that $64M is deferred, scheduled to be paid in 2022-26.
Greinke has been awesome this season, going 6-2 with a 2.89 ERA and 0.87 WHIP in 11 starts. He has made 10 quality starts in a row. He offers reliability, durability, upside, efficiency and he can certainly help with his bat. Having Greinke is almost like having another hitter. He's 8 for 25 (.320) with two homers, a triple and two doubles this season and has been among the best hitting pitchers every year since 2013.
Because Greinke is 35 and owed so much money, any team after him would have to give up less in prospects than it would for another pitcher in his tier. The Diamondbacks are retooling, and even though they've exceeded expectations by playing .500 baseball in their first 50 games, they would welcome an opportunity to get out from under that contract, which had the highest per-year value in MLB history at the time Greinke signed it.
According to a radio report from USA Today's Bob Nightengale, who is based in Phoenix, the Phillies had a scout at one of Greinke's recent starts specifically to look at him. Teams have scouts everywhere this time of year but that does at least signal interest on the Phillies' part.
Madison Bumgarner
We've mentioned Bumgarner here quite a bit over the last six months because everyone knew the 2019 Giants would be a disaster and that Bumgarner's free agency was approaching.
Bumgarner, unlike Greinke, would be a half-season rental. He can block a trade to the Phillies and several other contending teams, a strategic component of his contract designed to increase his leverage. When a player has one of these clauses, he can use it to add urgency to contract extension talks with the pursuing team or some sort of trade bonus from his current team.
Bumgarner had shown signs of decline the last two seasons with lower strikeout rates, higher ERAs and far fewer innings pitched. This season, he's off to a promising start, striking out 9.3 batters per nine innings compared to 7.6 last season, along with one of the lower walk rates of his career. His fastball velocity is also about a full mile per hour higher than it was last season.
Bumgarner is not as efficient as Greinke. Bumgarner deals with a lot of foul balls these days and is typically at 100 pitches through six innings. He's gone deeper than six just twice this season.
Like Greinke, Bumgarner also helps with his bat, and he has one of the strongest postseason track records of any pitcher ever.
Though he'd be a potential rental, Bumgarner will still cost the Phillies or any team a young player they aren't enthused about trading.
When weighing Greinke vs. Bumgarner, another consideration is that Greinke has pitched better the last two years in one of the five most hitter-friendly parks in the game, while Bumgarner has been performing in the best park for pitchers.
Mike Minor
Minor is a left-hander the Phillies have shown interest in during recent trade seasons and offseasons. Once upon a time, he was a big pitching prospect for the Braves, but things didn't go as planned in Atlanta and it took him until close to his 30th birthday to find stability and consistency.
After a dominant season in the Royals' bullpen in 2017, the Rangers took a chance on Minor as a starter and it has paid off. In 38 starts for Texas since the beginning of 2018, Minor is 17-11 with a 3.74 ERA and 1.12 WHIP while pitching for a bad team in a haven for hitters.
Minor is owed about $6.4 million more this season and $9.5 million next season. Those are affordable and attractive salaries for a mid-rotation starter. Because of that affordability, the Rangers will rightfully look for a solid trade package for him.
It's too early to speculate what any of these trade packages would look like specifically, but from least to most, it seems like it would go Greinke, Bumgarner, Minor, with Minor commanding more than Bumgarner only because he's under contract longer.
Click here to download the MyTeams App by NBC Sports! Receive comprehensive coverage of your teams and stream the Flyers, Sixers and Phillies games easily on your device.
More on the Phillies
After a heart-attack special in Wrigley, Phillies head to Milwaukee and another test
Phillies jump out to big lead, hang on to salvage split with Cubs
Hamels honors DPM and says finishing career in Philly has always been a thought
Phillies send Cole Irvin to minors, buy time on next move and Velasquez decision
