MIAMI - The Phillies know they will be without their starting catcher for approximately a month. They are less certain about their slugging cleanup hitter.

Both Carlos Ruiz and Ryan Howard underwent MRI examinations Monday in Philadelphia, and the news was not welcoming for the Phillies. Ruiz will miss three to four weeks with a right hamstring strain. Howard received a cortisone injection Sunday for inflammation in his left knee. His examination was troubling. For now, the team is labeling him "day-to-day."

Phillies head athletic trainer Scott Sheridan said there are "changes" to Howard's left meniscus (cartilage) and those "concern us." He said it is inconclusive as to whether Howard has torn it. The team should know how serious the damage is judging by Howard's reaction to the injection.

Could it be that Howard's ruptured left Achilles tendon contributed to this new knee injury?

"That's the million-dollar question right there," Sheridan said. "For me, it's like the old song - the foot bone is connected to the knee bone. . . . They all play a part. So that's a reasonable question. Whether that's what's happened, we don't know."

It is actually a $125 million question. Howard is owed that amount over the length of his five-year contract, which began in 2012. Howard has played 112 games since that deal started and is hitting .229 with a .716 OPS and 20 home runs. This season, he is batting .245 with six homers and 22 RBIs.

The organization is not yet concerned about its investment, assistant general manager Scott Proefrock said.

"You never know what's going to happen," Proefrock said. "Chase [Utley] signed a seven-year deal and we lost out on two years. Injuries are a part of the game. That comes with the territory when you sign these guys. We have a bunch of pitchers on long-term contracts, too. It's just a risk you take."

Howard, 33, said Sunday that the knee had bothered him since spring training, but Sheridan disputed that Monday, saying the symptoms happened for "a couple of weeks." He said there is a piece of Howard's meniscus that is abnormal compared to a normal meniscus. The tests conducted Monday were mixed; some suggested a meniscus tear and others did not.

Sheridan said it is a common injury that players will play through.

"I would bet there are a ton of guys who've had tears in their meniscus," he said. "On this team or on others. It's part of wear and tear and playing the game for 162 times and whatever else. These guys, it's their legs. With pitchers, it's the shoulder.

"The goal is to make him better and be done with it. But I don't know if that's going to happen. We're going to do the treatment that we did and see how he responds to it. And then we'll have to make decisions from there as to what needs to be done beyond that."

For Ruiz, the injury represents the latest setback in a cursed season. He missed the first 25 games because of a suspension for using Adderall. He suffered a Grade II hamstring strain in the second inning Sunday while running the bases. He is batting .235 with two RBIs.

Ruiz, 34, is a free agent at season's end. This is the fifth straight season he has required a stint on the disabled list. The catching duties will be shared by Erik Kratz and Humberto Quintero while he is absent. Phillies catchers are among the worst in baseball in many offensive categories.

"We're comfortable with what we have," Proefrock said. "We're not going to stop looking, but I don't think we're actively out there pursuing anything."

Adams on DL

To make room for Quintero on the roster, reliever Mike Adams (back strain) was placed on the 15-day disabled list. But because the move was retroactive to May 11, he can return as early as Sunday. The target is Monday in Boston.

"The pain subsided," Adams said. "I need to get in throwing shape."

Adams will go to Clearwater, Fla., and could throw a bullpen session Thursday and appear in a game situation Saturday.

Extra bases

The Phillies will not officially place Ruiz on the disabled list until Tuesday when they activate Tyler Cloyd for his start. . . . Pitching prospect Adam Morgan was scratched from his scheduled Monday start at triple-A Lehigh Valley with what the team termed a minor shoulder issue. He is expected to miss one start.