RHP Roy Oswalt makes his 2012 major league debut in the Texas Rangers’ series opener Friday against the Colorado Rockies at Rangers Ballpark in Arlington. Rookie LHP Christian Friedrich is the Rockies’ scheduled starter. Here’s the matchup:

Oswalt (0-0, 0.00): The Rangers called Oswalt to the majors after he made four minor league starts to get ready. … In his last minor league start, he threw 100 pitches in six innings, allowing two runs and a walk and striking out five Sunday with Triple-A Round Rock. … It will be his first start since, as a member of the Philadelphia Phillies, he lost Game 4 of the 2011 National League Division Series to the St. Louis Cardinals. … Oswalt’s last regular-season outing was Sept. 27, 2011, when he threw six scoreless innings against the Atlanta Braves. … In his 11-year major league career, Oswalt is 159-93 with a 3.21 ERA with the Houston Astros and Phillies.

Friedrich (4-3, 5.60): The struggling Rockies have gone to a four-man rotation of Josh Outman, Alex White, Jeff Francis and Friedrich after sending Jeremy Guthrie to the bullpen. … Friedrich has dropped his last two starts, allowing 12 runs (10 earned) in nine innings. … He has a 2.10 ERA on the road in five games. … The former first-rounder made his major league debut on May 9, giving up two runs (one earned) in six innings against the San Diego Padres. … He was 3-1 with a 5.59 ERA in May and is 1-2 with a 5.63 ERA in June.

Hitters: Of the seven current Rockies who have faced Oswalt, Todd Helton is 8-for-29 with two doubles, two home runs and three RBIs. ... Michael Cuddyer is 3-for-8 with a double, a home run and two RBIs. ... Carlos Gonzalez is 0-for-6 and Wil Nieves is 0-for-5. … Friedrich has yet to face any of the Rangers.

Up next:

Sat. at Rockies: RHP Colby Lewis (6-5, 3.00) vs. LHP Josh Outman (0-3, 8.41 ERA), 2:05 p.m., ESPN Dallas 103.3 FM/1270 AM/FSSW
Sun. at Rockies: LHP Matt Harrison (9-3, 3.41) vs. RHP Alex White (2-5, 6.06), 6:05 p.m., ESPN Dallas 103.3 FM/1540 AM/FSSW