CLEARWATER, Fla. -- Philadelphia Phillies manager Joe Girardi says he thinks pitching around the majors in April will be a battle of attrition following the shortened spring training.

The Phillies open the regular season at home on April 8 against the Oakland Athletics, the first of 13 straight days of games.

"I think that's a pretty good way of putting it, you know," Girardi said Monday before the Phillies played Baltimore in spring training. "It's a concern I'm sure for every organization in the game, and our situation is tough where it's 13 in a row. Just got to find a way through it and keep everybody healthy, that's the most important thing."

Teams are expected to have rosters expanded from 26 players to 28 in April, which would allow Girardi to have 15 active pitchers.

Solid defense, always a key, will be magnified with starters still building up and extensive use of bullpens.

"The most important thing for this team is, secure the baseball, right?" Girardi said. "Plays we need to make we need to make however you make them, too. You can fall down and catch popups, I don't care. Just catch them, they count."

Zack Wheeler, who went 14-10 with a 2.78 ERA and led the majors with 213 1/3 innings over 32 starts last year, threw live batting last Saturday and will do it again in the next few days. He experienced shoulder soreness in December but appears on target to be ready for the first week of regular-season games.

"Wheeler is doing great," Girardi said.

Wheeler is expected to make one spring training start before the Phillies break camp next week.

Aaron Nola will start Philadelphia's regular-season opener for the fifth consecutive year.

Girardi also said that left-hander Ranger Suarez, who arrived late to spring training because of visa issues, should start pitching in games soon. He had an 8-5 record with a 1.36 ERA in 39 games last year, including 12 starts.

The Phillies, who faded late last season, are coming off a year in which they finished at 82-80, good for second place in the National League East.

The Associated Press contributed to this report.