LHP Jon Lester (14-8, 3.12 ERA) vs. RHP Jake Arrieta (4-6, 5.10 ERA)
The Sox are in need of a sure thing. There may be no greater certainty in all of baseball than Lester against the Orioles.
Lester is 12-0 with a 2.00 ERA in 15 career starts against Baltimore. That trend has been even more severe in 2010. In three outings vs. the O's the lefty has allowed just one run in 19 innings (0.49 ERA), going 2-0 in the process.
Arrieta, a 24-year-old rookie, will be facing Boston for the first time. He has lost each of his last three starts while posting a 4.30 ERA.
The righty has 46 walks and 39 strikeouts in 83 innings this year.
Marco Scutaro, SS J.D. Drew, RF Victor Martinez, C David Ortiz, DH Adrian Beltre, 3B Mike Lowell, 1B Jed Lowrie, 2B Mike Lowell, 1B Daniel Nava, LF Ryan Kalish, CF
Brian Roberts, 2B Julio Lugo, SS Nick Markakis, RF Ty Wigginton, 1B Adam Jones, CF Felix Pie, LF Matt Wieters, C Nolan Reimold, DH Josh Bell, 3B
Designated hitter David Ortiz is 0-for-9 with eight strikeouts against Baltimore lefty Brian Matusz.
Boston has scored three runs or less in five straight games.
For his career third baseman Adrian Beltre is six RBIs shy of 1,000 and five runs shy of 900.
Designated hitter Luke Scott has four home runs in his last nine games.
Right-hander Koji Uehara is 5-for-5 in save opportunities since assuming the closer's role and has given up just one run in his last 14 innings.
Right fielder Nick Markakis ripped his 40th double Tuesday night. He has reached that mark in four straight seasons.
BLACK AND BLUE
Second baseman Dustin Pedroia had his broken left foot put back in a boot Thursday, where it will stay for seven days. After one week, he will either continue his rehab or face season-ending surgery.
Outfielder Jacoby Ellsbury has another broken rib near where he was hurt earlier in the year, the result of a collision at first base in Texas. He will likely miss the remainder of the season.
Center fielder Mike Cameron had season-ending surgery Friday 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) continues to try to recover from a broken right foot. He has yet to be able to run at full speed, one of the last major obstacles before he can eye a rehab stint.
Catcher Jarrod Saltalamacchia is on the DL after recovering from an infection in his lower right leg. He is with the team and will be activated Wednesday.
Outfielder/second baseman Eric Patterson (neck strain) went 4-for-13 with three stolen bases in three rehab games at Pawtucket. He will also be activated from the DL on Wednesday.
Right-hander Junichi Tazawa underwent Tommy John surgery in March. He is out for the year.
Right-hander Jason Berken will likely miss the remainder of the season with a slightly torn right labrum and a frayed rotator cuff.
Right-hander David Hernandez is expected to return in September from a sprained left ankle.
Considering Lester's track record in this series and the fact that Arrieta is still a work in progress, this is a game the Red Sox must win. There just isn't time left to squander golden opportunities.