GARY — Charle Rosario is the oldest starting pitcher on the RailCats' roster at 28.
He was still in high school and 16 when Greg Tagert brought the four-man rotation to Gary.
Alex Gunn, in his second stint with the 'Cats, was 13 years old.
Yet, Gunn didn't bat an eye when he was traded to the RailCats from Laredo and told he'd be starting in a four-man rotation.
Most professional teams use a five-man, as seen in Major League Baseball for the last 30 years.
In the 1970s, the four-man rotation was king, allowing pitchers to throw more innings in a season and still finish complete games.
"Over the years, the four-man rotation gets talked about more than I'd want it to," Tagert said. "It's because it sounds abnormal to people. It doesn't sound abnormal to me; it sounds routine."
Tagert grew up a fan of the 1970s' Oakland A's.
He started using a four-man rotation in 2003 when he managed in Kenosha (Wisconsin) in the Frontier League. He brought it to the RailCats in 2005 with pitchers he knew could handle taking the ball on three days' rest and promptly won a Northern League Championship.
He admitted that the farther and farther players are from the 1970s — and even early '80s when the four-man was still used sparingly — it is harder and harder to convince pitchers to join the RailCats' rotation.
"To be honest, it's been a challenge that has grown greater over the years, because the players are farther removed from the time period when it was usual," Tagert said.
His oldest player — first baseman/designated hitter Frank Martinez — was born in 1985. No pitcher was born before 1987.
The key to success in the four-man rotation is routine. Three days' rest means that the bullpen days come quicker, and the mental preparation allows for quick turnover.
"It helps being able to improve on your mistakes," Gunn said. "You pitch more innings, and you have fewer days to dwell on your last start. It allows you to work on changing a grip, and it speeds up improvement."
Gunn had six starts and threw 42 2/3 innings for the RailCats before his contract was purchased by the Arizona Diamondbacks last season. He then threw 59 innings for the D'backs Rookie League team and the Kane County Cougars, picking up four starts.
"At first, it freaked me out a little," Gunn said, "but then I realized I got to pitch more and play more."
'Cats pitching coach Alain Quijano played three seasons in a four-man rotation, as the team's ace in 2013.
"It's hard to convince players, because they know what they're used to seeing on TV," Quijano said. "In high school and college, they'll pitch once a week. In the pros, they see a five-man. Here, you get the ball on three days' rest.
"It's a tough sell. I've had people tell me 'you're joking, right?'"
Rosario embodied the tough sell last season, selected to the American Association All-Star Game and he finished second in the league in innings pitched to St. Paul's Mark Hamburger, 158 2/3-155 1/3. Hamburger led the league in complete games with seven, and Rosario had four.
Rosario led the league with 24 starts in 2016.
"I've heard people say, 'the velo is down because guys are on the four-man,' or 'you don't have the legs, because the guys are on the four-man,'" Quijano said. "If you study Charle, usually his fourth start on three days rest, he'll still touch 92 (mph)."