Seattle Mariners (18-21) at Baltimore Orioles (17-20), 12:35 p.m. (ET)

(SportsNetwork.com) - Baltimore right-hander Chris Tillman tries to put the brakes on a personal four-game losing streak Thursday when the Orioles wrap up a three-game set with the Seattle Mariners at Camden Yards.

Tillman was scratched from Sunday's outing due to back stiffness, but appears to be ready after coming through a bullpen session on Tuesday with no issues. However, he has given up 18 runs over his last four starts and is 2-5 on the year with a 6.34 ERA.

"Things went well for him today," Baltimore manager Buck Showalter said after the bullpen session. "He feels good. He's 100 percent and ready to go."

Tillman, though, stands a terrific chance of getting untracked, as he is a perfect 6-0 in six starts versus the Mariners with a 2.03 ERA. Seattle, of course, drafted him in the second round back in 2006 before sending him, Adam Jones and three others to the Orioles in 2008 for left-hander Erik Bedard.

Seattle, meanwhile, will turn to lefty J.A. Happ, who is 3-1 with a 2.98 ERA. Happ did not get a decision on Friday against Boston, as he allowed a run and five hits in seven innings of his team's 2-1 win.

He has only walked nine batters in 45 1/3 innings this season and has produced a quality start in six of his seven outings.

Happ has faced the Orioles eight times (7 starts) and is 2-3 against them with a 2.93 ERA.

Seattle evened this series at a game apiece on Wednesday, as Roenis Elias tossed 7 2/3 strong innings, and the Mariners held on for a 4-2 win.

Elias (1-1) sailed through the first six innings and did not allow a runner to reach scoring position until the seventh. Fernando Rodney gave up a run in the ninth but eventually recorded his 10th save.

Justin Ruggiano's two-run home run keyed the Mariners' attack, and Nelson Cruz had another two-hit game against his former club.

Wei-Yin Chen (1-3) allowed all four Mariners runs on eight hits in seven innings, and Adam Jones had three of Baltimore's 10 hits.

"He left a couple breaking balls up that that he paid for, but other than that he was crisp," said Showalter. "Pitched deep into the game."

Baltimore went 5-2 against Seattle last season and has won 10 of the last 14 head-to-head meetings inside Camden Yards.