O'Sullivan remains the favorite to open the year as the Phillies' fifth starter, the team's official site reports.

The Phillies haven't made an official announcement yet, but they sent Miguel Alfredo Gonzalez to Triple-A earlier this week and released Kevin Slowey on Tuesday leaving O'Sullivan as the last man standing from the rotation candidates. GM Ruben Amaro Jr. said the Phillies would look outside the organization as well, so O'Sullivan is no lock for the job. The team will not need a fifth starter until April 12.

O'Sullivan is considered the favorite to open the year as the Phillies' fifth starter, the team's official site reports.

O'Sullivan was sent to minor league camp earlier this month, but is stretched out while Kevin Slowey has been pitching in relief. The Phillies do not need a fifth starter until April 12. If O'Sullivan does get the nod, his stint in the rotation will be short lived as Chad Billingsley is expected to be ready to come off the disabled list before the end of April.

Manager Ryne Sandberg indicated Wednesday that O'Sullivan remains in competition for the final spot in the Phillies' rotation, CSN Philadelphia reports.

O'Sullivan was sent to minor league camp earlier this month, but has been pitching on the same day as Miguel Alfredo Gonzalez, who also remains in the mix for a starting spot along with Kevin Slowey. Whomever earns the starting spot will have a limited opportunity to make an impression before Chad Billingsley is ready to join the rotation in mid-to-late April.

O'Sullivan was reassigned to minor league camp Monday.

He'll begin the season at Triple-A as a depth option for the Phillies with the hope of pushing his way into the mix for a spot start at some point in 2015.

O'Sullivan allowed one run on two hits with a walk and two strikeouts in three innings against the Yankees on Sunday.

O'Sullivan has seen his chances at earning a roster spot improve since camp began. With Cliff Lee possibly needing surgery and Miguel Alfredo Gonzalez failing to impress, the opportunity is there for O'Sullivan to get in the mix for a starting or long relief job. Kevin Slowey and Paul Clemens are also in the mix with O'Sullivan for a roster spot.

O'Sullivan signed a minor league deal, which includes a spring training invite, with the Phillies on Monday, Stephen Gross of The Morning Call reports.

O'Sullivan, who was released by Philadelphia in October, went 6-10 with a 4.30 ERA in 148.2 Triple-A Innings last season. He made three appearances for the Phillies, allowing nine earned runs, including three homers, in just 12.2 innings.

The Phillies have released O'Sullivan, the Philadelphia Inquirer reports.

O'Sullivan was designated for assignment earlier this week. He was 0-1 with a 6.39 ERA in three games for the Phillies this season.

O'Sullivan was outrighted Monday to make room on the 40-man roster, The Morning Call's Stephen Gross reports.

O'Sullivan went back and forth between Triple-A Lehigh Valley and the big league club last season, but had little success at either level.

O'Sullivan was recalled from Triple-A Lehigh Valley on Friday, the Philadelphia Daily News' Ryan Lawrence reports.

He has a 6.94 ERA in two starts (11.2 innings) with the Phillies this season while posting a 4.30 ERA in 148.2 innings in Triple-A, so there's very little upside here. It's possible that O'Sullivan could get a start or two down the stretch, but right now it appears much more likely that he'll just pitch out of the bullpen.

O'Sullivan was outrighted to Triple-A Lehigh Valley on Wednesday, Chris Cotillo of MLBDailyDish.com reports.

Rather than electing free agency, O'Sullivan will stick with the Phillies organization despite his lack of encouraging outings at both Triple-A and with the big club. Even so, he'll likely have a rotation spot waiting for him back at Lehigh Valley, where he went 5-9 with a 4.57 ERA and 1.37 WHIP over 124 innings.

O'Sullivan was designated for assignment Sunday.

The team indicated earlier in the week that O'Sullivan's rotation spot would not be in jeopardy after he surrendered five runs (including three homers) in six innings Thursday vs. the Astros, but that changed when Jerome Williams became available off waivers. Williams is expected to immediately displace O'Sullivan in the rotation and start Tuesday vs. the Angels.

O'Sullivan will stay in the Phillies' rotation and will make his next start Tuesday, the Philadelphia Inquirer reports.

O'Sullivan took Roberto Hernandez's rotation spot after he was traded to the Dodgers last week. He will face the Angels on Tuesday.

O'Sullivan made a spot start against Houston on Thursday, allowing five runs and seven hits in six innings, He issued two walks and struck out four.

Roberto Hernandez was supposed to start Thursday, but he was traded to the Dodgers earlier in the day, so O'Sullivan was called up from Triple-A Lehigh Valley. He settled down nicely after allowing three homers early in the game, including a pair of long balls to slugger Chris Carter. If Philadelphia decides to keep O'Sullivan in the rotation, his next start would be on the road against the Angels.

O'Sullivan will start Thursday's game against the Astros, MLB.com's Brian McTaggart reports.

The Phillies traded Thursday's starter, Roberto Hernandez, to the Dodgers during the day, so they decided to call up O'Sullivan to take his place in the rotation. O'Sullivan started one game for the Phillies earlier this season and gave up four earned runs over 5.2 innings in a home loss to the Braves.

The Phillies selected O'Sullivan's contract from Triple-A Lehigh Valley on Thursday, Todd Zolecki of MLB.com reports.

O'Sullivan takes the roster spot of Roberto Hernandez, who was traded to the Dodgers. He last pitched on Aug. 2, which presumably means he will start in place of Hernandez on Thursday night.

Phillies sent RHP Sean O'Sullivan outright to Triple-A Lehigh Valley.

O'Sullivan cleared waivers after being designated for assignment by the Phillies over the weekend. The 26-year-old has the option to reject the assignment to Triple-A and choose free agency.

Phillies designated RHP Sean O'Sullivan for assignment.

O'Sullivan allowed four earned runs in 5 2/3 innings in a spot start Saturday versus the Braves. He seems likely to clear waivers and remain in the organization as depth.

Sean O'Sullivan surrendered four earned runs in 5 2/3 innings Saturday in a loss to the Braves.

It was the second the half of a doubleheader and the Phillies lost both games. O'Sullivan did not walk a batter, but the Braves got to him for eight hits. He'll likely be sent back to Triple-A on Sunday morning.

Phillies purchased the contract of RHP Sean O'Sullivan from Triple-A Lehigh Valley.

O'Sullivan is starting for the Phillies in the second half of Saturday's doubleheader against the Braves. The right-hander will be sent back to Triple-A on Sunday.

Sean O'Sullivan will start the second game of Saturday's doubleheader against the Braves.

He'll follow Roberto Hernandez. Signed to a minor league deal over the winter, O'Sullivan holds a 4.31 ERA with 47 strikeouts over 87 2/3 innings at Triple-A Lehigh Valley this season. He should be avoided in fantasy leagues.