Ryan Mattheus (chest) will throw live batting practice Monday.

It will be the first time he's faced hitters since being diagnosed with costochondritis, which is inflammation of a tendon in his chest. There's a chance that Mattheus will still have time to get ready for Opening Day.

Ryan Mattheus (chest) was cleared to resume throwing after a checkup with Nationals trainers Tuesday.

Mattheus was shut down for about two weeks with costochondritis -- inflammation of a tendon in his chest. He will hope to catch up to the other relievers in Nationals camp before the start of the 2014 regular season.

Ryan Mattheus (chest) has yet to be cleared to resume throwing.

Mattheus is dealing with costochondritis, which is inflammation of a tendon in his chest. He's expected to start throwing again at some point later this week and should still have time to get ready for the season if he can avoid setbacks.

Ryan Mattheus said Tuesday that he's dealing with costochondritis, which is inflammation of a tendon in his chest.

It's good news under the circumstances and the expectation is that Mattheus may need to rest for one or two weeks. However, he could be cutting it close to be ready for the season.

Ryan Mattheus (chest) may be shut down for 1-2 weeks.

Mattheus underwent an MRI this weekend for an upper chest injury. "There's a joint in there that connects the cartilage to the sternum. I think I might have irritated the cartilage or an intercostal muscle or messed a rib up or something," the right-hander told reporters on Sunday. "I felt it after my second bullpen." This could obviously affect his ability to be 100 percent ready on Opening Day.

Ryan Mattheus has been shut down since last Tuesday due to an upper chest injury.

Mattheus underwent an MRI but is still waiting on the results. Obviously, more will be known about his status once the results are known. "There's a joint in there that connects the cartilage to the sternum. I think I might have irritated the cartilage or an intercostal muscle or messed a rib up or something," Mattheus said. "I felt it after my second bullpen."

Nationals recalled RHP Ryan Mattheus from Triple-A Syracuse.

Mattheus holds an ugly 6.26 ERA in 23 innings this season at the major league level. He'll be used in the middle innings.

Nationals optioned RHP Ryan Mattheus to Triple-A Syracuse.

Mattheus has a rough 6.26 ERA in 23 innings this season at the major league level. He was booted off the 25-man roster Thursday to clear a spot for Drew Storen.

Nationals activated RHP Ryan Mattheus from the 15-day disabled list.

He'll be the 26th man for Friday's doubleheader against the Mets but will surely stick around after that. Mattheus has been out since mid-May with a fractured hand.

Ryan Mattheus (hand) is shifting his minor league rehab assignment to Triple-A Syracuse.

Mattheus allowed one run in four innings at Double-A Harrisburg and showed decent velocity with his fastball. He will be back in the Nationals' bullpen by the end of July and can be asset in the second half.

Ryan Mattheus (hand) will move his rehab assignment Tuesday to Double-A Harrisburg.

Mattheus has been out since mid-May with a fractured right hand, but returned to game action last week. He remains on track to be activated from the disabled list later this month.

Ryan Mattheus (hand) will begin a rehab assignment with the Gulf Coast League Nationals on Friday.

Mattheus began throwing from a mound a week ago and is ready to test things out in game action. He's been out since mid-May and will probably require a decent number of rehab appearances.

Ryan Mattheus threw off a mound Friday for the first time since he broke his hand in May.

Nationals manager Davey Johnson said everybody was impressed with the way Mattheus threw. He could begin a rehab assignment within 10 days, which likely puts him on track to rejoin the Nats' bullpen by the end of the month.

Ryan Mattheus is scheduled to throw off a mound Friday for the first time since he broke his hand in May.

Mattheus recently said that he's aiming to begin a rehab assignment later this month. Look for him to rejoin the Nationals' bullpen in August.

Ryan Mattheus (hand) has thrown from a distance of 60 feet each of the past two days.

Mattheus is currently working his way back from a broken right hand, which he suffered when he punched a locker in frustration in May. He hopes to begin a rehab assignment in about four weeks, which means he likely won't rejoin the Nats' bullpen until August.

Ryan Mattheus (hand) played catch on Thursday for about 10 minutes.

It's the first time he's done so since fracturing his right hand when he punched his locker in frustration. Mattheus should return sometime next month.

Ryan Mattheus is expected to be sidelined 4-6 weeks with a fractured right hand.

Mattheus won't require surgery, but since the injury is to his pitching hand he can't do a whole lot while out. He'll have to build his arm strength back up once out of his cast.

Nationals placed RHP Ryan Mattheus on the 15-day disabled list, retroactive to May 20, with a fractured right hand.

Mattheus suffered the injury Sunday after he gave up five runs on four hits and two walks over one inning against the Padres and punched his locker in frustration. No word yet on how long he'll be sidelined, but he's obviously facing an extended absence. The Nationals are calling up Yunesky Maya and Fernando Abad for some bullpen insurance.

Nationals activated RHP Ryan Mattheus from the 15-day disabled list.

Mattheus reportedly "looked great" in his latest rehab appearance, and will return to a middle relief role with the Nationals. He's replacing Brad Lidge on the active roster.

According to MASN.com's Byron Kerr, Ryan Mattheus (foot) ''looked great'' in his latest rehab appearance with Double-A Harrisburg.

Mattheus hasn't reported any complications as he recovers from plantar fasciitis in his left foot. If all goes as planned, he should return to the Nationals sometime in late-June.