The team said Howard would be immobilized for approximately one to two weeks. He could begin weight training as soon as a month from now, depending on his recovery.
If Howard must start the season (and his five-year, $125 million contract) on the disabled list, the Phillies could turn temporarily to John Mayberry Jr. at first base.
Mayberry, though, could figure prominently into the team's plans for left field in 2012.
"He proved that he can be a good big-league player," manager Charlie Manuel said. "He will get every chance in the world to be a regular player."
Of all major-league hitters with at least 300 plate appearances in 2011, Chase Utley had the second-worst line drive rate in baseball. Only the Los Angeles Angels' Vernon Wells had a lower percentage of liner hits than Utley's 12.7 percent. He simply did not drive the ball like he did in the past.
That's one of the reasons, Amaro said, that Utley will work to strengthen his legs this winter. Utley missed the first two months of the season with patellar tendinitis. He was able to manage the pain with an altered training and stretching program under head athletic trainer Scott Sheridan.
But Utley's .769 OPS was his lowest in a season of at least 94 games played.
"I don't think it's behind him," Amaro said of the injury. "The way he managed it and Scott Sheridan managed it was incredible. He was in the lineup every day. One of the things that he and Scott and I have talked about is to make sure that he stays strong. There may be times when he may need more days off over the course of the season.
"More importantly, we're working on ways for him to strengthen his legs. That is one of the things that he wasn't able to do and affected his power. He was not able to squat and some other exercises because of the injury and what's going on in his knees. He's going to have to go about it different ways. We're going to go about different ways to make him stay strong."
Minor-league outfielder Tyson Gillies, acquired in the Cliff Lee trade in 2009, was 3 for 7 with five walks and four runs scored in his first three Arizona Fall League games. Gillies played only three games in 2011 because of nagging hamstring injuries.
Contact staff writer Matt Gelb
at email@example.com or @magelb on Twitter.