Yusmeiro Petit emerged as one of the most dominant relievers in baseball this season, but he hasn't been able to translate that success in his opportunities as a starter.
Perhaps facing the injury-beset Colorado Rockies can help him settle in as he closes in on a historic mark.
Petit will take aim at the all-time record for consecutive batters retired when he takes the mound for the San Francisco Giants in Thursday's series finale against visiting Colorado.
San Francisco (70-62) announced Monday that Petit would be swapping places with starter Tim Lincecum, who was 1-3 with a 9.49 ERA in his last six outings.
Petit is 1-2 with a 6.32 ERA over six starts compared to 2-1 with a 1.84 ERA in 27 relief appearances. He's thrown 16 1-3 scoreless innings in his last nine appearances while giving up two hits and striking out 24 of 51 batters.
Petit (3-3, 3.59) has retired 38 straight batters, seven shy of the major league record set by Mark Buehrle in 2009.
It's unclear whether Petit will remain in the rotation beyond Thursday.
"We'll make that call on the next start after this Petit start," manager Bruce Bochy said.
Petit gave up five runs over five innings in his last start as San Francisco won 9-6 in 14 innings at Philadelphia on July 22. He's 1-0 with a 1.93 ERA in four relief appearances versus Colorado this year and 1-1 with a 5.53 ERA in six career starts against the Rockies (53-79).
The right-hander will face a Colorado team that has scored five runs with 12 hits over the last three games. The Rockies' already depleted roster took another hit Wednesday when catcher Wilin Rosario went on the 15-day disabled list, joining Troy Tulowitzki, Michael Cuddyer and Carlos Gonzalez. Those players finished Nos. 1-4 last season on the team in RBIs, combining for 315 with 92 home runs.
Petit will likely have to look no further than his red-hot catcher for run support. After homering twice in a 3-0 win Tuesday, Buster Posey hit a two-run walkoff shot in Wednesday's 4-2 victory.
The 2012 NL MVP is 15 for 31 with five homers and 10 RBIs during a seven-game hitting streak.
"He's hot right now," said Colorado's Corey Dickerson, who hit his 20th homer Wednesday. "We've got to figure a way to get him out."
Hunter Pence has hit .465 with 12 runs in his last 12 matchups with Colorado, which will send Jordan Lyles (6-1, 4.05) to the mound. The right-hander has posted a 2.80 ERA over his last six road outings, though AT&T Park is the lone NL stadium he has yet to pitch at in his career.
Lyles was charged with three runs while walking five over 5 2-3 innings of Colorado's 5-4, 13-inning win against Miami on Saturday.
He's 1-0 with a 2.70 ERA in two starts against the Giants, last facing them with Houston on Aug. 30, 2012, when he gave up three runs over five innings. Pence is 2 for 5 with a homer against Lyles.