TORONTO -- Jason Hammel threw a bullpen session in Toronto on Tuesday that checked out fine, clearing the way for him to start Thursday's pivotal series opener against the Yankees at Camden Yards.

Hammel, who hasn't pitched since July 13 after undergoing right knee surgery, will fly to Baltimore on his own Wednesday afternoon before the Orioles finish their three-game set in Toronto.

"He's physically fine, it's not a medical thing anymore," Orioles manager Buck Showalter said. "They signed off on that. He's physically ready to go."

Hammel's pitch count will be limited, but Showalter wouldn't specify any exact details.

The right-hander is 8-6 with a 3.54 ERA over 109 1/3 innings this season. Showalter believes his small workload will benefit the club down the stretch run, as it battles for the division title.

"It's like making a pretty good September trade," Showalter said.

With Hammel starting Thursday, Wei-Yin Chen will get an extra day of rest and start Friday.

MRI on Tillman's elbow comes back negative

TORONTO -- The Orioles received some good news on Tuesday, as an MRI on right-hander Chris Tillman's elbow came back negative.

Team orthopedist Dr. John Wilckens saw the same thing that the MRI showed, which was just some inflammation in the elbow.

"All structure is good, ligament, everything," Orioles manager Buck Showalter said. "The nerve is a little inflamed, but that's normal at this time of the year."

The plan is for Tillman to go to Bowie, where the Orioles' Double-A affiliate resides, and get some exercise before his next start, which has yet to be determined.

Showalter said Tillman would need four or five days, at least, provided there is no further discomfort in the elbow.

"We're hoping to not give an anti-inflammatory shot, and I think we're going to be able to stay away from that," Showalter said.

Tillman, who experienced stiffness from the beginning of his last outing against the Yankees on Sunday, until he was removed after three innings, is 7-2 with a 3.39 ERA over 11 starts this season.

With the uncertainty of Tillman's status, and Showalter wanting to get rookie Miguel Gonzalez extra rest at some point this month, the Orioles could turn to a six-man rotation. Showalter wouldn't go as far as saying it, but starter Jake Arrieta, who has made 10 starts at Triple-A Norfolk, is likely to join the team soon.

"Fortunately, we have some depth to pick from and some guys that are ready to pitch and that includes Steve Johnson and Jake Arietta," Showalter said.

"He [Arrieta] has pitched real well down there his last three of four starts. He has always had good stuff, he's just commanding the ball better."

Arrieta went 3-9 with a 6.13 ERA with the Orioles over 18 starts before being sent to Norfolk.

Tidbits

• The Orioles announced on Tuesday that there will be a new ticket promotion to celebrate the team's push for the postseason, in what is the 20th Anniversary of Oriole Park at Camden Yards.

In an effort to encourage fans to "BUCKle Up!" and Back the Birds, the team will offer discounted prices for select locations during the Orioles' series against the Rays Sept. 11-13.

For all three games of the series, while supplies last, Eutaw Street Bleacher seats are $4.00 (regularly $19) and all Left Field Lower Box seats are $8.00 (regularly $32). Fans who already purchased regularly priced seats in the Eutaw Street Bleachers or Left Field Lower Box will receive a refund for the difference in ticket value.

The team is encouraging fans to use the hashtag #BUCKleUp on Twitter throughout the remainder of the season to promote the Orioles' push for the postseason.

• Jim Thome is feeling better and will visit a specialist Thursday regarding the herniated disk in his neck that has kept him sidelined since July 27. There is no timetable for his return.

• Troy Patton (sprained right ankle) threw up to 120 feet Tuesday for 10 minutes, which was 30 feet and two minutes longer than he threw on Monday. He is likely to throw from 120 feet again this week.