PITTSBURGH -- The last time the Cubs went through a rebuilding process, the foundation was built through impact position players. When the time came to construct October-ready rosters, the bulk of the featured arms were acquired via trades or free agency.

There is growing optimism around the Chicago organization that homegrown pitching depth can now be an area of strength as the club tries to emerge from this latest period of reconstruction. If that grows from theory to reality in the coming seasons, it can help the Cubs plan how to best target outside additions.

"There's just areas right now where we might be a little short," manager David Ross said. "You go out and try to fill those in with proven big leaguers, and then you try to have something that the Minor Leagues is facilitating and feeding you for depth. And it looks like pitching is going to be a strong point of that, hopefully."

In Friday's 6-5 win over the Pirates at PNC Park, rookie Javier Assad offered one example of the kind of pitcher Chicago can begin to consider for its 2023 rotational depth chart. Assad was barely on the radar during Spring Training, but the righty is one in a line of homegrown arms who have made great strides within the farm system's improved pitching infrastructure.

Assad's latest outing was underwhelming (three earned runs allowed over four innings), but his body of work -- 2.99 ERA with 134 strikeouts and 52 walks in 135 2/3 innings across Double-A, Triple-A and the Majors -- and his developmental gains, specifically an increase in velocity this year, gives the Cubs plenty to think about.

"They put themselves on radar with the work they did," Ross said. "I think in Assad's case, adding some velocity in the offseason and working towards that and taking it from a guy that can pitch at 91-92 [mph], and now he's got a couple of ticks up. It's 94 at times. You look at that and you think about how many guys can put in the work to add a mile an hour to their pitch ability like he did, or two miles an hour. That's a game changer."

Down the stretch, Assad and fellow rookie Hayden Wesneski have been given the chance to rack up some starts to gain experience, while being evaluated. Prospect Caleb Kilian touched the Majors earlier this season and will be on the radar for 2023 as well.

This homegrown wave for the current rotation began with Justin Steele, Keegan Thompson and Adbert Alzolay last year. For the bullpen, internal arms like Brandon Hughes, Erich Uelmen and Jeremiah Estrada broke into the Majors this year. On both fronts, the list of pitchers knocking on Chicago's door is getting longer.

"I think there's a lot of talent in the lower levels right now," Assad said via Cubs interpreter Will Nadal. "I think that they're advancing as well, the same as me. I've been very impressed throughout the whole year with all the pitchers that we have in the lower levels. And I think that we're going to have a bright future."

The Cubs overhauled their pitching infrastructure from the top down entering the 2020 season, reorganizing the leadership and the layers of coaching at each level. The pandemic-shortened season stunted the initial growth, but there have been organizational gains when it comes to velocity training, pitch design and identifying the types of pitchers to target in trades, the Draft and internationally.

"Changing the infrastructure takes time -- period," Ross said.

Ben Brown (No. 7 on Pipeline's Top 30 Cubs prospects list), Wesneski (No. 12) and Kilian (No. 14) were all brought into the fold in Deadline trades the past two seasons. The Cubs selected Jordan Wicks (No. 5) with their first-round Draft pick in 2021 and then followed suit with Cade Horton (No. 4) in a '22 class that featured 16 pitchers in 20 selections.

There are 15 pitchers on the Cubs' Top 30 list, and that only scratches the surface of the arms that could continue to reach the Majors across the 2023 and '24 seasons. It is a layer of potential depth that could position the front office to narrow its free-agent wish list.

"In a perfect world all of your talent would be homegrown," Cubs director of pitching Craig Breslow said last month. "But I think what we see is we're getting a clearer picture of the guys that we have in our system who are going to contribute to Major League wins. And then alongside that, you have a chance to kind of complement and fill in spaces."

If the in-house pitching lives up to the potential, the front office can narrow the wish list on the free-agent market. Right now, it looks like the Cubs will need to be aggressive in adding an impact bat or two. The North Siders will be in the market for at least one impact rotation arm, plus some late-inning relief help.