Aaron Nola took the mound Tuesday night having thrown 139 innings this season between double A, triple A and the major leagues.
The Phillies don't want their 22-year-old righthander logging many more than 170 or 180 innings this season, his first full year as a professional. To prolong his season and that of fellow rookie Adam Morgan, the team is considering using a six-man starting rotation in September.
"We'll have the flexibility to do that at that time," general manager Ruben Amaro Jr. said. "That's something that we've talked about. It's a possibility. There's a couple guys who could come up and be that sixth guy.