5 paths the St. Louis Cardinals can take to find a fifth starter

Ever since Steven Matz went down with a lower back strain on May 1st, the Cardinals have struggled to fill his spot in the rotation. Some off days early in the month allowed the team to get by with just 4 regular starting pitchers, but Matthew Liberatore has had to fill in for three starts that would have otherwise been Matz's. The front office has botched this situation thus far.

As of now, there is no timetable regarding Steven Matz's return. The last update, per John Denton of MLB.com, was that Matz hadn't begun a throwing program as of May 12th. He instead received another pain-killing injection. Matz hasn't resumed playing catch at any distance, and his 15-day stint could quickly transition into a 60-day IL placement if he doesn't show improvement soon.

Libby was an excellent reliever before transitioning back to the rotation. He was a starting pitcher in the minors, but his struggles in that role in St. Louis pushed him to be a reliever this year. While Liberatore wasn't featured in the back of the bullpen -- those spots have been reserved for Andrew Kittredge, JoJo Romero, and Ryan Helsley -- he played the important role of bridging starters to those three.

Below you'll find Libby's splits this year as a starter and a reliever.

It is clear (and has been since 2022) that Matthew Liberatore has not been a successful starting pitcher in the majors. Whether this is attributable to a lack of fastball velocity when being extended, hitters understanding him better the third time through the order, or a multitude of other issues, it's clear now that Matthew Liberatore is not built to be a starting pitcher for the Cardinals, at least for now.

That has forced the team's hand. Now, they must scramble to find a fifth starter to take Matz's place in the rotation. The team has some internal choices in the minors, but there are also a couple of outside options that could help the team in the near and distant future. The Cardinals could promote or sign a true fifth starter -- someone who will give the team a fighting chance to win but not blow anyone out. They could also make a move for another high-end guy to bolster the rotation for the long haul.

Here are 5 pitchers who could become the fifth starter for the St. Louis Cardinals.

Tink Hence

Bringing up Tink Hence, a 21-year-old who has pitched fewer than 100 innings of baseball in AA, would be the boldest of decisions. The Cardinals promoting a pitcher from Double-A has a brief history (Jordan Hicks for one), so they'll be extremely hesitant to do it this time.

Hence has two major factors playing in his favor: he lines up perfectly, and he's extremely talented. Hence last pitched on the 18th, so he'll be ready to pitch on the 23rd, which would be this Thursday. The Cardinals have an off day, so he would even get an extra day of rest, which may behoove him given his increased usage this year.

Hence is also quite talented. He's the organization's #2 ranked prospect on most lists, though Masyn Winn will graduate when the next batch comes out. Hence has a career 3.49 ERA, 1.179 WHIP, and 11 Ks/9. While some of those figures are bolstered by success at the lowest levels in baseball, his showing last year and this year has been promising.

What goes against Hence being promoted would be his age, inexperience, and a couple of less-than-ideal starts recently. He threw just 3.2 innings on May 12th, and he gave up 9 runs (none of them earned) with only 1 strikeout and 3 walks. The start prior to that Hence pitched just 4.1 innings, and he allowed 6 runs to score. He struck out 5 batters, but he walked 2 and allowed 7 hits. This was a blow-up start.

Hence has still pitched well this year in the minors; He has a 3.18 ERA, 1.084 WHIP, and he's striking out more than 10 batters per nine innings while allowing few home runs. It would be uncharacteristic and premature for the Cardinals to promote Tink Hence right now to the starting rotation, but it would be an interesting test for the organization's best pitching prospect in a long time.

Zack Greinke

I'm starting off this list with the two least likely options. Zack Greinke is only marginally more likely than Tink Hence, if that. Greinke is currently a free agent, and he's been working out in Arizona to stay as fresh as can be should a call come his way.

Greinke absolutely fits the age minimum to be a starting pitcher on the Cardinals in 2024, as he is 40 and will remain so until late October. When the 2023 season ended, Greinke wasn't quite sure if he would return for another season. The 20-year veteran has already racked up quite a few accolades including a Cy Young Award, 6 Gold Gloves, 6 All-Star selections, a 2-time ERA leader, and a couple of World Series appearances.

Greinke's showing these past two seasons has left a lot to be desired. He played for the Kansas City Royals, the team that drafted him 6th overall in the 2002 MLB draft. He has pitched a total of 279.1 innings between 2022 and 2023 with a 4.38 ERA, 4.39 FIP, 1.307 WHIP, and just 5.5 strikeouts/9 innings. Greinke hasn't walked many batters, but he's been prone to allowing hits often.

If the Cardinals were to sign Greinke, it would be only temporarily unless he shows promise. If he has flashes of his excellence, then Steven Matz can move to the bullpen upon his return, a place where he saw success last year. Don't expect much out of Greinke, but at least Oli Marmol can keep Liberatore in the bullpen, a place where he, too, is seeing more success. Greinke's track record gives Marmol a bit more confidence rolling him out every 5 days as well.

Zack Thompson or Andre Pallante

The Cardinals optioned left-handed Zack Thompson to AAA Memphis on April 24th with outfielder Jordan Walker. The plan for Thompson was to get stretched out to potentially help as a starter this year or next. He has been yo-yoed his entire career.

Before being demoted, Thompson was used as a reliever, and he had a 9.53 ERA in just 17 innings pitched in the majors. Since joining Memphis, Thompson has pitched 14.2 innings in 3 starts (4 appearances); he has a 1.84 ERA, 1.295 WHIP, and he is striking out almost 9 batters per nine innings. He hasn't pitched more than 4 innings in a start, but his pitch count has incrementally increased with each game.

Andre Pallante was having a terrible start to his year in St. Louis. He threw 10 innings with only 6 strikeouts, a 6.30 ERA, and a 1.900 WHIP. His slider and sinker were getting destroyed, and he was quite ineffective. Pallante, like Thompson, was demoted to build up and increase his bulk abilities. He has pitched in 4 games (all starts), and he has a 2.20 ERA with 9 strikeouts in 16.1 innings pitched with the Memphis Redbirds. While Pallante has been good at limiting runs, he has continued to walk batters at an excessive rate. He has 13 walks to just 9 strikeouts in Memphis.

Thompson last pitched on the 15th, so his schedule doesn't line up very well, and Pallante pitched on the 17th, so his next start doesn't exactly fit the bill either. Both of these pitchers could use more fine-tuning in the minors, so while it's possible one of the two is called upon, it's not likely.

Sem Robberse

Sem Robberse is the best option available internally to replace Steven Matz and Matthew Liberatore as the fifth starter. Robberse has done all he needs to in the minors, and it's nearing time that he gets his chance in St. Louis with the big league club.

The Cardinals acquired the Dutchman when they traded Jordan Hicks to the Toronto Blue Jays at last year's deadline, and Robberse has not disappointed. The right-handed starter has pitched exclusively in Memphis this year, and he has a 3.29 ERA, .210 batting average against, and 1.04 WHIP in 54.2 innings (9 starts) this year.

Robberse started off the season as one of the organization's best minor league pitchers in April. He had an 8-inning, 9-strikeout outing on April 19th, and he followed that up by pitching 7 innings and only allowing 2 runs to score on April 26th.

May has been a bit of a struggle for Robberse, as he has two outings where he's given up 6 runs -- one with 4 home runs on May 8th. His 5.04 ERA in May is a bit concerning, but he has still been able to put together an admirable season.

Robberse last pitched on May 19th, so he is perfectly lined up to slot in as the team's fifth starter. Calls for Sem to be promoted have only grown in volume since Matz went down, and it's seeming more and more likely with each passing day that he will be chosen to pitch this next time around the rotation.