No matter how Arizona Diamondbacks manager Kirk Gibson structures his starting rotation, he's being let down more often than not.
The Diamondbacks' 5.75 overall ERA is the worst in the majors, while their starters have a 7.50 mark and have failed to pitch six full innings 13 times. Mike Bolsinger was the latest to get his first start after replacing Trevor Cahill in the rotation, but he allowed seven runs in four innings as Arizona (5-15) fell 8-6 on Saturday.
After being spotted a 4-0 lead, Bolsinger couldn't hold it and failed to get an out in the fifth before being removed. He was charged with four of the five runs in the inning.
Paul Goldschmidt and Martin Prado drove in two runs apiece for Arizona, which has dropped seven of its last eight - a stretch that began with a three-game sweep at the hands of the Dodgers last weekend.
Collmenter will try to give Arizona a much-needed solid start in this contest.
After coming out of the bullpen for his first four appearances, Collmenter (0-1, 3.75 ERA) replaced Randall Delgado in the rotation. He wasn't much better, though, giving up three runs and five hits in four innings of a 7-3 loss to the New York Mets on Monday.
"Not good enough," Gibson said of Collmenter's outing. "He didn't get the ball exactly where he wanted it. Balls were up in the zone out over the plate. We asked him to do a lot. I didn't think he was really in sync, but he went out there and busted his tail."
The right-hander is 3-5 with a 5.06 ERA in four starts and eight relief appearances against the Dodgers. He allowed one run and three hits while walking two in one inning of relief in a 7-5 loss to Los Angeles on March 23 in Australia.
The Dodgers (11-7) have outscored the Diamondbacks 42-27 while winning six of seven meetings this season. Andre Ethier hit a three-run homer in the fourth Saturday, while Adrian Gonzalez and Matt Kemp each went 2 for 4 with a pair of RBIs.
Los Angeles totaled seven runs while dropping three of its previous four.
"We're never out of a game, especially with the offense that we have," Kemp said. "We have a lot of guys who can drive the ball our of the ballpark. We just need to get guys on base. And if we continue to do that, we'll be very successful."
Josh Beckett will get the start for the Dodgers as he seeks some consistency.
Beckett (0-0, 4.00) was erratic in Tuesday's 3-2, 12-inning loss to San Francisco, walking five in five innings. It marked his most free passes since also allowing five against Detroit on May 29, 2011, while with Boston, but he didn't allow a run and gave up only two hits.
"I burned myself in the fourth inning with a lot of taxing pitches," Beckett said. "It would have been nice to give the bullpen more of a breather."
The right-hander has pitched at least eight innings three times while going 2-2 with a 2.19 ERA over his last five starts against the Diamondbacks, striking out 39 and walking just six over 37 innings.