TORONTO -- Another change to the Blue Jays pitching staff is on the horizon. It appears as though right-hander Victor Zambrano will no longer be making his next start, which was scheduled for Sunday against the Devil Rays.

Zambrano could be moved back into the bullpen, where he started the season, or sent outright to the Minor Leagues to continue to build up his arm strength. On May 2, Zambrano replaced Josh Towers in the Jays rotation, but was unable to pitch his way out of the third inning in either of his two starts. On Tuesday night, Zambrano was pounded by the Red Sox for eight runs on eight hits in just 2 2/3 innings of work and saw his ERA as a starter rise to 16.88.

Jays general manager J.P. Ricciardi played coy prior to Wednesday's game versus the Red Sox about what changes would be made.

"I think we'll have something to say about that later in the week," said Ricciardi, when asked if Zambrano would be allowed to start on Sunday.

According to Toronto manager John Gibbons, these type of changes are bound to happen over the course of a season. That doesn't mean he has lost faith in his players, though.

"When things happen sometimes you make changes," Gibbons said. "We did that with Towers early on, but I'm not going to abandon my team. This is my team and if we need to adjust something, then we'll adjust something. But I'm not ready to give up on anybody."

With starter Gustavo Chacin about to begin rehabilitating his strained left shoulder, the Jays may only need a short-term replacement in the rotation. Chacin has been out since April 30, when he had a bullpen session cut short because of pain in his left shoulder. The 26-year-old will be eligable to come off of the 15-day disabled list on Monday, but it's unlikely he will be able to return to the Major League roster until closer to the end of the month.

Chacin hasn't participated in any baseball activities since injuring his shoulder. Ricciardi indicated that the left-hander would begin playing catch on Saturday, which would mean Chacin rested his arm for a period of 11 days. After working back on to a mound, Ricciardi said it's likely that Chacin will need a few Minor League rehab outings before rejoining Toronto's rotation.

"He won't come back right away," Ricciardi said. "He's going to have to go out and throw a little bit first."

Toronto could opt to call someone up from Triple-A as a temporary replacement until Chacin is able to return, or they could potentially promote right-hander Casey Janssen from the bullpen. As a rookie last season, Janssen went 6-10 with a 5.22 ERA in 17 starts. The 25-year-old has been impressive out of the bullpen for the Jays this season. He's allowed only two earned runs in 16 1/3 innings of work.

Thomson update: One pitcher who won't be considered for a starting spot is right-hander John Thomson. According to Ricciardi, the veteran starter recently developed a blister on his throwing hand in his first rehab start at Triple-A. The injury comes at a bad time for Thomson, because in that Thursday start he allowed just one earned run on two hits in 5 2/3 innings while striking out three.

Thomson has been on the 15-day DL with a right shoulder injury since March 31. After he made his first rehab start with Class A Dunedin on April 23, the Jays had 30 days to decide whether to call him up to the Major Leagues or assign him to one of their Minor League affiliates. Due to his latest injury, the Jays have been granted an extra 10 days and now will not have to make a decision about Thomson's status until around the first week of June.

Thomson doesn't have an opt-out clause in his contract, but Ricciardi said he'd consider an attempt to move the pitcher if Thomson requests as much.

"If he comes to us and says he wants an out, we won't give him an out," Ricciardi said. "But we'll try and accomodate him if he doesn't think it's going to work out here."

Lights out: Entering Wednesday night's game, Jays right-hander Jeremy Accardo and lefty Scott Downs had yet to give up an earned run this season. They had combined to throw 24 innings of shutout baseball while allowing only 11 hits with 26 strikeouts. Downs also leads the team with 15 appearances.

Did you know? After Tuesday night's loss to the Red Sox, the Jays losing streak was extended to seven games. The streak started on May 1 and is the longest losing skid to start any month in club history since the team dropped 10 straight games from June 1-11, 1981.

Coming up: Jays ace Roy Halladay (4-1, 3.59 ERA) is scheduled to take the mound for Toronto when the Blue Jays host the Red Sox at 7:07 p.m. ET on Thursday at Rogers Centre. Boston will counter with knuckleballer Tim Wakefield (3-3, 2.11 ERA).