During the Chicago Cubs’ last rebuild, one of the main criticisms of the organization was its’ struggles with developing pitching. During most of the last few years, the organization frequently had to make free agent signings or significant trades to address issues in the bullpen and starting rotation.

Over the last few seasons, the narrative has started to shift surrounding the Cubs. Keegan Thompson and Justin Steele, among others, are two of the first pitchers to recently graduate from the Cubs minor league system and have MLB success.

Thompson’s Development and Role in the MLB

When Keegan Thompson was first promoted to the MLB last season, he served mainly in a long-relief role. The Cubs weren’t sure where the Auburn standout would have the most success. As a reliever who could use his best stuff across a shorter outing, or as a true starting pitcher.

He made a series of starts at the end of the 2021 season, but none of them were longer than four innings. The start of 2022 saw a similar strategy, with his first seven appearances of the year all coming in relief.

Thompson’s relief outings were all dominant. At the end of those seven relief appearances to start the year, Thompson had an ERA of 1.17. The second-year pitcher worked 13.2 scoreless innings across four outings to start the year.

After the strong start to the season out of the bullpen, the Cubs, following a series of pitching injuries, started to use Thompson as a starting pitcher. The Cubs had used a similar developmental plan with Adbert Alzolay and Steele, who both began their careers in the bullpen before moving to the starting rotation.

So far, Thompson may be having the most success of the three who have followed this developmental plan. His first start in 2022, against the San Diego Padres, was a solid four innings in which he allowed two earned runs. He followed that up with a spectacular five-inning shutout performance against the Pittsburgh Pirates that lowered his season ERA to 1.41.

Thompson’s last two starts in May were solid, but three consecutive tough starts to begin June presented some concerns. A three-run outing against the Cardinals was arguably the shakiest Thompson had looked on the mound all year, and a seven earned run outing in a road trip against Baltimore followed by another tough start against the Yankees added even more concern.

Since then, Thompson has been back to the form he showed at the start of the season. His last two starts have been nothing short of spectacular; six innings, no earned runs, and nine strikeouts against the Braves and six innings with one run allowed in a winning effort against the Pirates.

Throughout the last month, the Cubs and pitching coach Tommy Hottovy have been working with Thompson to increase his pitch count and learn how to manage his energy across a start. There have been some struggles, namely the three-start stretch at the start of this month, but the overall results have still been good.

For the season, Thompson’s fastball velocity has held at about 94 mph, which is around the league average, despite his move into the starting rotation and the longest outings of his career. The deeper attributes on the pitch remain outstanding, with a spin rate in the 91st percentile of all fastballs and solid movement attributes that could still improve based on the elite spin he puts on the pitch.

His secondary pitches still need some development, something the Cubs pitch lab and staff should be able to help with. His curveball has sharp movement downward but has still been hit hard, and the Cubs and Thompson probably need to refine where he throws it in or out of the zone and in what counts it is most effective.

Thompson’s changeup has had solid metrics backing its’ performance but is still a pitch he doesn’t go to often that needs development, although he has thrown it more in recent weeks. His sinker and cutter, meanwhile, both have solid metrics when it comes to break, and the cutter has been one of his most effective pitches, but also still have room for development.

While Thompson has taken some dramatic steps forward in his development over the last few months, there is still a lot of room for improvement. Room for improvement isn’t a bad thing, however, for a pitcher that already has an ERA of 3.10 across 61 innings this season.

There are still developmental steps to be taken regarding Thompson’s pitch mix, and likely the spin efficiency of his four-seam fastball, cutter, and sinker. The transition to starting will impact how the Cubs and Thompson strategize the pitch mix they feel gives him the best chance for success.

As those developments continue, Thompson could get even better. His pitches all have very good underlying qualities, and once the Cubs find the formula to maximize his pitches, he could take another big step forward.

What this Means for the Cubs Moving Forward

The Cubs are entering what appears to be another rebuild, or at the very least a restructuring, ahead of their next opportunity to win a World Series. One of the main challenges, and reasons the Cubs are where they are right now, was the franchise’s difficulty in developing homegrown pitching.

Thompson’s development represents a significant step forward for the franchise. He has already found success using pitches the Cubs front office and coaching staff has helped him develop. The changes he has made to work on his pitch mix have improved his performance; with more room to grow.

This bodes well for pitchers like Caleb Kilian, the prospect who was one of the players the Cubs received in the Kris Bryant deal last year. Kilian has added a few new pitches to his arsenal during his time with the Cubs, and like Thompson, prioritizes a cutter, sinker, four-seam fastball, and curveball along with a developing slider. The developmental strategies used with Thompson could also help Kilian as he begins his MLB career.

The Cubs are clearly taking steps forward in pitching development, and now have a group of young pitchers who already have, or are about to, take the next step in or towards the major leagues. Continuing to improve the pitching development process will be vital for the franchise’s future and ability to have sustained success.