O'Sullivan will make his next start on Monday against the Dodgers, the Phillies' official site reports.

O'Sullivan was at risk of losing his rotation spot, but Aaron Harang went on the disabled list Thursday leaving the Phillies with little choice but to stick with O'Sullivan for now. He has allowed six earned runs and double-digits in hits in each of his last two starts.

O'Sullivan took his sixth loss Monday against the Brewers as he gave up six runs on 12 hits and a walk over five innings.

O'Sullivan has now given up more runs than innings pitched in three starts, including each of his last two. O'Sullivan is at least an effective innings eater -- he's made it into the fifth inning in every start this year. For the rebuilding Phillies, that's pretty much all that matters. His ERA is up to 5.76.

O'Sullivan struggled mightily Tuesday, allowing six runs in 4.1 innings against the Yankees.

The righty was battered for four home runs in his 4.1 inningsmatching a season-high set last month against the Mets. O'Sullivan will carry a 5.34 ERA and 1.50 WHIP into his weekend start against the Nationals.

O'Sullivan was solid in a no-decision Thursday, whiffing a season-high seven Orioles while allowing one run on four hits over five innings.

After a leadoff home run by Manny Machado, O'Sullivan shut things down, but he still didn't go long enough for a quality start. Nonetheless, this was an enormous improvement over O'Sullivan's recent work, as he'd allowed 18 runs while posting a 4:8 K:BB in 28.1 innings in his last four starts. He heads to New York to face the Yankees on Tuesday, and it wouldn't be surprising to see the bad O'Sullivan reemerge.

O'Sullivan gave up four runs on eight hits and four walks in six innings Saturday, striking out one.

He's now been tagged for 18 runs in 23.1 innings over his last four starts, sending his ERA soaring to 5.08. O'Sullivan's giving the Phillies innings though, and without any better options in the minors he'll likely remain in the rotation for the time being. His next start will come on Thursday, at home against the Orioles.

Sullivan allowed four runs on nine hits with a walk and a strikeout over 5.2 innings in Tuesday's win versus the Reds.

Following back-to-back quality starts, Sullivan has allowed 11 runs in his last 11.1 innings to raise his ERA from 3.54 to 5.03. Although he kept the ball in the park after allowing four home runs in his previous start, Cincinnati did their damage against Sullivan with four doubles. He is scheduled to face San Francisco at home on Sunday.

O'Sullivan (1-4) gave up seven runs on 11 hits over 5.2 innings in Wednesday's 7-0 loss to the Mets.

Four of those 11 hits were homers, including a pair by Lucas Duda and one to dead center by opposing starter Noah Syndergaard. O'Sullivan entered the game with a surprisingly competent-looking 3.54 ERA and 1.14 WHIP over his first two starts, but his newly inflated stats (4,81, 1.31) are closer to his true level. He doesn't miss many bats and the Phillies don't win many games, so the best thing you can do with O'Sullivan in fantasy is stack hitters against him in daily leagues. His next start, Wednesday against the Reds, presents a good opportunity to do just that.

O'Sullivan allowed two runs on five hits, walking one and striking out three over six innings, but was the hard-luck loser as the as Phillies dropped a 2-1 decision to Washington on Friday night.

O'Sullivan (1-3, 3.54 ERA) turned in another solid performance, but he ran up against Max Scherzer and the red-hot Nationals and took the loss. Not overpowering, and without the raw stuff to dominate, his early season performance has been a bit of a surprise, so it may be wise temper your expectations as the season progresses.

O'Sullivan pitched six scoreless innings Sunday against the Diamondbacks to pick up his first win of the season.

O'Sullivan allowed five hits, walked two and struck out four in the outing. The win was his first in the majors since May 12, 2011. He has a 3.68 ERA and a 13:6 K:BB ratio in 22 innings this season. His next start will come against the Nationals.

O'Sullivan gave up three earned runs on five hits and one walk with two strikeouts over five innings Tuesday against the Pirates.

This was his first start after spending three weeks on the disabled list with a knee injury. The upside here is extremely limited, as O'Sullivan does not miss a lot of bats (10.8 percent career K-rate) and he is also not great at preventing runs (5.87 career ERA).

O'Sullivan (knee) has been confirmed as the starting pitcher for Tuesday's game against the Pirates.

O'Sullivan will return to action after spending over three weeks on the disabled list. He will square off a Pirates team that averaged 5.4 runs per game over its last five contests.

O'Sullivan (knee) will come off the disabled list Tuesday to start for the Phillies, the Philadelphia Inquirer reports.

O'Sullivan, who has been sidelined with left knee tendinitis, will face the Pirates on Tuesday. He is 0-1 with a 4.91 ERA in two starts for the Phillies this season.

O'Sullivan (knee) said he should only need one rehab outing before returning from the disabled list, the Philadelphia Inquirer reports.

O'Sullivan will make a rehab start Thursday with Low-A Lakewood and is expected to throw 70-to-80 pitches. He is lined up to pitch for the Phillies on May 12, the next time the team needs a fifth starter.

O'Sullivan (knee) will start a rehab assignment Thursday with Low-A Lakewood, the Phillies' official site reports.

O'Sullivan threw two simulated innings on Saturday to test out his knee. The Phillies have not announced how many rehab starts he will make before coming off the disabled list.

O'Sullivan (knee) said he expects to come off the disabled list when his 15 days are up, the Philadelphia Daily News reports.

O'Sullivan was placed on the disabled list Wednesday with tendinitis in his left knee. He may not return to a starting role when he is activated as Chad Billingsley should be ready to join the Phillies' rotation in early May.

O'Sullivan was placed on the 15-day DL on Wednesday with left knee tendinitis.

O'Sullivan's injury likely surfaced following his last start last Friday. It's unclear how long he will need to sit, but he should be sent on a short rehab assignment when he's nearing the date. Fortunately, the issue is in his leg rather than the arm, so he should be able to do some drills to keep it in shape while he's on the shelf.

O'Sullivan allowed four runs on five hits, including two home runs, over five innings in a loss to the Nationals on Friday.

O'Sullivan struck out two and walked two in the outing. He likely has two or three more starts left before Chad Billingsley is ready to come off the disabled list and bumps O'Sullivan from the rotation.

O'Sullivan allowed two runs over six innings against the Nationals on Sunday. He struck out five and walked one.

A solid start for O'Sullivan, who went up against Max Scherzer in the game. He is temporarily filling a rotation spot until Chad Billingsley is ready to come off the disabled list. He will face the Nationals again in his next start.

O'Sullivan was called up to the Phillies for Sunday's game against the Nationals.

O'Sullivan will get the start against Washington, but not much should be expected from him. The 27-year-old holds a 5.91 ERA across four teams in his career and has allowed a brutal 1.6 HR/9. He isn't much more than a fill-in starter.

O'Sullivan will start Sunday's game against the Nationals, Ryan Lawrence of the Philadelphia Daily News reports.

O'Sullivan was the favorite to get the nod Sunday, and Thursday's announcement confirms that he will do just that. He appeared in three games with the Phillies last season, starting two, and allowed nine earned runs on 15 hits over 12.2 innings.