I'd take my chances with that foursome. In fact, for one month back in the 2013-14 offseason, the four were teammates in the Pittsburgh Pirates organization. Cole was the former No. 1 overall pick who had reached the majors in 2013. Morton had started 20 games in 2013 and would start 26 in 2014. Glasnow was an up-and-coming minor league prospect. In November of that offseason, the Pirates acquired Mikolas from the Padres in a deal for Alex Dickerson. A month later, they traded Mikolas to the Rangers for Chris McGuiness, who never played in the majors for Pittsburgh.
The ex-Pirates rotation of players currently competing in the division series would be playoff-worthy. In fact, if you need a fifth starter, you can add J.A. Happ to the rotation. Those five combined for 17.6 WAR in 2019, which would rank third among actual 2019 rotations, behind only the Nationals and Astros. The 2019 Pirates rotation? It ranked 29th in the majors with 1.5 WAR.
Pirates fans -- on the heels of a miserable 69-93 season that ended with the departure of manager Clint Hurdle (but not general manager Neal Huntington) -- are probably viewing this postseason through a different lens. The eight teams competing in the division series feature 17 ex-Pirates on the rosters. Cole and Morton are the two most prominent, but there is also Glasnow and Rays teammate Austin Meadows, who hit .291 with 33 home runs in a 3.8-WAR season in his first full year in the majors.
The Rays acquired those two from the Pirates at the 2018 trade deadline for Chris Archer. While Meadows and Glasnow combined for 6.4 WAR, Archer went 3-9 with a 5.19 ERA and 0.7 WAR. Cole, meanwhile, has been worth 12.1 WAR in his two seasons with the Astros. The four players acquired for him have produced a combined 2.9 WAR over two seasons. The best of the lot in 2019 was pitcher Joe Musgrove, worth 1.7 WAR.
Those two epic trade failures have crushed the Pirates' immediate future. Remarkably, however, the Pirates are not the franchise with the most WAR from ex-players populating the eight remaining playoff teams. Using the active rosters for the division series, I tabulated the 2019 WAR of ex-players for all 30 franchises (a player only had to have been a member of the organization at some point in his career, not necessarily in the major leagues). Oakland, who made it to this year's AL wild-card game, actually leads the way:
Athletics: 29.1 WAR
Among the prominent ex-A's: Josh Donaldson (6.1 WAR), Max Muncy (5.7), Nelson Cruz (4.3), Edwin Encarnacion (2.8), Emilio Pagan (2.4) and Will Harris (2.1). Muncy has been one of the unlikeliest stars of the past two seasons after the Dodgers claimed him on waivers from the A's. Encarnacion and Harris never actually played for Oakland, but they briefly passed through the organization. The Donaldson trade to the Blue Jays after the 2014 season ranks as one of Billy Beane's biggest mistakes, but how about trading Cruz away back in 2004 for Keith Ginter? (Cruz is also an ex-Met, ex-Brewer, ex-Ranger, ex-Oriole and ex-Mariner.)
The Diamondbacks traded Zack Greinke to the Astros this year -- after losing Patrick Corbin to the Nationals as a free agent. They also drafted Max Scherzer back in 2006, but they traded him to the Tigers as a young major leaguer (netting Ian Kennedy and Edwin Jackson in the deal). Paul Goldschmidt, Wade Miley, Harris, Dansby Swanson, A.J. Pollock and Didi Gregorius are some of the other famous ex-Diamondbacks.
Scherzer is also part of the ex-Tigers rotation that would still be good if it had been kept together: Scherzer, Justin Verlander and Anibal Sanchez. Rays shortstop Willy Adames went to Tampa in the David Price trade and had a 4.2-WAR season. Players like Chad Green, Shane Greene, Cameron Maybin and Matt Joyce provided value to 2019 playoff teams. The 2019 Tigers lost 114 games.
Here's the complete list:
Arizona Diamondbacks: 16 players, 28.7 WAR; best ex Max Scherzer
Atlanta Braves: 11 players, 13.4 WAR; best ex Charlie Morton
Baltimore Orioles: 15 players, 21.0 WAR; best ex Nelson Cruz
Boston Red Sox: 11 players, 12.9 WAR; best ex Anibal Sanchez
Chicago Cubs: 12 players, 27.6 WAR; best ex Josh Donaldson
Chicago White Sox: 3 players, 2.7 WAR; best ex Avisail Garcia
Cincinnati Reds: 8 players, 11.0 WAR; best ex Justin Turner
Cleveland Indians: 15 players, 28.1 WAR; best ex Josh Donaldson
Colorado Rockies: 9 players, 14.5 WAR; best ex DJ LeMahieu
Detroit Tigers: 12 players, 28.1 WAR; best ex Justin Verlander
Houston Astros: 11 players, 17.5 WAR; best ex Charlie Morton
Kansas City Royals: 5 players, 7.9 WAR; best ex Zack Greinke
Los Angeles Angels: 17 players, 25.7 WAR; best ex Patrick Corbin
Los Angeles Dodgers: 9 players, 15.9 WAR; best ex Zack Greinke
Miami Marlins: 13 players, 11.5 WAR; best ex Anibal Sanchez
Milwaukee Brewers: 15 players, 28.5 WAR; best ex Michael Brantley
Minnesota Twins: 7 players, 8.4 WAR; best ex Anibal Sanchez
New York Mets: 9 players, 14.1 WAR; best ex Nelson Cruz
New York Yankees: 17 players, 15.7 WAR; best ex Giovanny Gallegos
Oakland Athletics: 15 players, 29.1 WAR; best ex Josh Donaldson
Philadelphia Phillies: 6 players, 13.3 WAR; best ex Charlie Morton
Pittsburgh Pirates: 17 players, 28.9 WAR; best ex Gerrit Cole
San Diego Padres: 9 players, 10.3 WAR; best ex Max Fried
San Francisco Giants: 9 players, 4.4 WAR; best ex Ehire Adrianza
Seattle Mariners: 16 players, 24.4 WAR; best ex Nelson Cruz
St. Louis Cardinals: 10 players, 11.1 WAR; best ex Tommy Pham
Tampa Bay Rays: 11 players, 14.7 WAR; best ex Robinson Chirinos
Texas Rangers: 10 players, 16.5 WAR; best ex Nelson Cruz
Toronto Blue Jays: 15 players, 27.0 WAR; best ex Josh Donaldson
Washington Nationals: 6 players, 4.8 WAR; best ex Asdrubal Cabrera (though Cabrera is now back with the Nats)
We can also use this study to see how the playoff teams themselves were built. Here are the number of homegrown players on each team's playoff roster, with 2019 combined WAR:
Dodgers: 15 (33.6 WAR)
Nine of the 12 pitchers on the staff are homegrown, although that includes international free agents Hyun-Jin Ryu and Kenta Maeda. Their two big free-agent signings for 2019 -- Pollock and Joe Kelly -- actually combined for minus-0.3 WAR.
Twins: 13 (28.3 WAR)
The Twins are an interesting mix. Kyle Gibson and Jose Berrios are the only homegrown first-round picks. Berrios and Eddie Rosario were drafted out of Puerto Rico. The international scouting department signed Jorge Polanco, Max Kepler, Miguel Sano, Luis Arraez and Brusdar Graterol. They hit on some later-round college guys like Mitch Garver (ninth round), Taylor Rogers (11th round) and Tyler Duffey (fifth round). Randy Dobnak was an undrafted free agent.
Cardinals: 12 (27.3 WAR)
The heart of the team is all homegrown: Yadier Molina, Jack Flaherty, Paul DeJong, Kolten Wong, Tommy Edman, Dakota Hudson and Matt Carpenter. Flaherty, Hudson and Wong were first-round picks. Molina was drafted way back in 2000. Adam Wainwright has spent his entire career with the Cardinals, although he was acquired from the Braves as a minor leaguer (in the J.D. Drew trade).
Astros: 9 (27.1 WAR)
Alex Bregman, George Springer and Carlos Correa are homegrown first-round picks. Jose Altuve was signed out of Venezuela in 2007. But the only homegrown pitchers are Josh James and Jose Urquidy. How did Jeff Luhnow manage to trade for Verlander, Cole and Greinke? Ridiculous.
Nationals: 8 (23.1 WAR)
Anthony Rendon, Stephen Strasburg, Juan Soto and Victor Robles are a powerful homegrown foursome. They stole Trea Turner from the Padres in a three-way trade that cost the Nationals only Steven Souza Jr. Scherzer and Corbin were big-money free agents.
Yankees: 7 (16.1 WAR)
Aaron Judge, Brett Gardner, Gary Sanchez, Masahiro Tanaka and Luis Severino top the homegrown list, but credit Brian Cashman for building depth around the edges with astute pickups like Gio Urshela (waivers), DJ LeMahieu (free agent), Gleyber Torres (trade) and Gregorius (trade).
Rays: 6 (9.4 WAR)
The Rays are pretty much a miracle, a small-market team building a playoff roster more via a long list of astute trades than through the farm system (which hit a lull for a few years but is now one of the best in the game). Blake Snell, Brandon Lowe, Kevin Kiermaier, Yonny Chirinos, Diego Castillo and Brendan McKay are the homegrown products and Morton the one free agent, but everybody else came via trade -- a bunch of castoffs, low-cost acquisitions and, other than Adames, lightly regarded prospects.
Braves: 5 (23.1 WAR)
Only five homegrown players, but what a five: Freddie Freeman, Ronald Acuna Jr., Mike Soroka, Ozzie Albies and Julio Teheran. (Brian McCann and Tyler Flowers were originally drafted by the Braves, left the organization and later returned.) Four members of the pitching staff were former first-round picks acquired via trade by previous front-office regimes as minor leaguers or unproven major leaguers: Mike Foltynewicz, Sean Newcomb, Max Fried and Luke Jackson.