What to expect from young Braves pitchers in future?

Braves rookie pitcher Matt Wisler had another ineffective outing last night. That's become a trend for Wisler and the other young starting pitchers the Braves hope will be part of the rotation in the future: Williams Perez, Mike Foltynewicz and Manny Banuelos.

Anyone still paying attention to the Braves and trying to be optimistic about those pitchers can look to the franchise's past. Sure they are struggling as first-year starters for the Braves but so did Tom Glavine, John Smoltz and Steve Avery. That's two Hall of Fame pitchers (Glavine and Smoltz) and another (Avery) who was a front-line starter until injuries derailed his career.

But how do most pitchers with first-year results similar to Wisler, Perez and Foltynewicz end up doing over their careers? I went to Baseball Reference to get some idea. (I excluded Banuelos because he's only made six starts this season.)

First thing is first: Glavine (nine starts) and Smoltz (12 starts) were bad in their first go-round but they weren't as bad as Wisler, Perez or Foltynewicz. Avery (20 starts) was even worse than those three, though, so there's that.

Among the current Braves rookie trio, Wisler has the best Wins Above Replacement at -0.3. Since 1980, 43 first-year pitchers with at least 15 starts had a WAR of -0.3 or worse. (See here for the full list.)

Among those 43 pitchers, 20 ended up having a career WAR of 0.0 or better. There are/were a handful of good starting pitchers among them: Avery, Javier Vazquez, Bobby Witt, Mike Leake, Derek Holland and Wandy Rodriguez.

Among the 20 pitchers on the list with neutral or positive WAR, five ended up pitching out of the bullpen for the majority of their careers. Two of them, Eddie Guardado and Mike (brother of Greg) Maddux, were effective relief pitchers for several seasons.

Obviously the list is limited by its endpoints. It doesn’t capture every pitcher because it starts at 1980. Nor does it include starting pitchers who struggled during their first season but made less than 15 starts, such as Glavine and Smoltz, because rookie pitchers who struggle tend to end up back in the minors or in the bullpen. There are of course lots of starting pitchers who were good as rookies and then had below-average careers.

There are lots of other variables to consider. The 43 pitchers on the list were different ages when they debuted. They pitched in different leagues over different years. They had different pedigrees—high draft picks typically get more time to prove themselves. WAR is an estimate of value, not a perfect measurement. And so on and so forth.

But the list gives some idea of what might be expected for the Wisler, Perez and Foltynewicz. Of the 43 pitchers since 1980 who started at least 15 games as rookies and were bad or worse than them: about half ended up being average or better, six became good starters and two were All-Star starting pitchers (Avery and Vazquez).

The Braves’ young trio could become effective starters after their rough rookie seasons but recent history shows it’s somewhat more likely they want.