As good as Buchholz has been against opposing teams this year, he's been impossibly better against the Blue Jays.
In 16 innings over two starts, he's allowed just two runs (one earned) on 12 hits and four walks, all while striking out eight.
His career numbers against Toronto aren't bad either, as he is 5-3 with a 2.79 ERA.
Marcum, meanwhile, is putting together an impressive season after missing the entire 2009 campaign due to Tommy John surgery.
He is 1-1 with a 4.50 ERA against the Red Sox. His first two starts against the Sox were excellent, when he went a combined 14 innings, giving up just one earned run. The third time around wasn't so pretty though, as he was rocked for eight earned runs in four innings on Aug. 11. Adrian Beltre and J.D. Drew homered, while Bill Hall homered twice in the 10-1 Red Sox win.
Marcum responded by pitching a complete-game, one-hitter at Oakland his last time out.
Lineups will be posted approximately four hours before pitch.
David Ortiz's 11-game hitting streak came to an end on Saturday. He went 0-for-5 with a pair of strikeouts.
Since taking a day off on Aug. 12, Marco Scutaro is on a tear. Playing through shoulder pain, Scutaro is batting .406 since Aug. 13 with four doubles and six runs scored. He went 3-for-3 to begin Saturday's game, giving him hits in five consecutive at-bats after going 2-for-2 on Friday.
Daisuke Matsuzaka pitched eight innnings on Saturday for third time this season.
Lyle Overbay homered again on Saturday after crushing a pair of three-run shots on Friday night. He now has 16 homers on the year.
Though Casey Janssen picked up the loss, the Blue Jays' bullpen used three pitchers to combine for thre scoreless innings on Saturday.
Shaun Marcum needed just 103 pitches to earn a complete-game victory over the A's his last time out. He gave up just one hit and walked just one batter as his ERA dropped from 3.87 to 3.69 in one outing.
BLACK AND BLUE
Second baseman Dustin Pedroia was placed on the 15-day disabled list Friday with soreness in his left foot. He played just two games after coming off the DL on Tuesday, having already missed nearly two months since first breaking the foot on June 25.
Outfielder Jacoby Ellsbury has another broken rib near where he was hurt earlier in the year, the result of a collision at first base Friday in Texas. He is out four to six weeks at minimum and will likely miss the remainder of the season.
Center fielder Mike Cameron will have season-ending surgery to repair an abdominal tear.
First baseman Kevin Youkilis had successful surgery to repair the torn right adductor muscle on his right hand. He will miss the remainder of the season.
Catcher Jason Varitek (broken right foot) received good news on Friday, as he will be able to continue his recovery program without fear of further injury. He won't play for at least a week, but he's not expected to suffer setbacks similar to those of Pedroa.
Catcher Jarrod Saltalamacchia is on the DL with an infection in his lower right leg. He will remain at Mass General Hospital until Monday, receiving IV fluids and antibiotics.
Catcher Kevin Cash is on the DL with a left hamstring strain. He caught for Pawtucket on Friday and will play a rehab game at Lowell on Sunday.
Left-hander Hideki Okajima is on the DL with a right hamstring strain.
Right-hander Junichi Tazawa underwent Tommy John surgery in March. He is out for the year.
Left-hander David Purcey was placed on the disabled list earlier this week with a sore right foot.
Right-hander Jesse Litsch is likely out for the year with a labral tear in his right hip.
Right-hander Dustin McGowan is out for the year following right shoulder surgery. He may miss all of 2011.
The Blue Jays are a feisty squad, and they could probably compete for a division crown if they were in either of the AL's other two divisions. As it is, they won't go quietly, and it's crucial that the Red Sox don't take any steps backward in this all-important homestand.
With a tired bullpen, much of that will depend on the right shoulder of Clay Buchholz. After Jon Lester, couldn't make it through the third inning on Friday, the team looks to its other ace for a series victory.