Oregon’s revised starting rotation led the Ducks to their first Pac-12 road sweep in four years at Utah.

George Horton will stick with the trio of Robert Ahlstrom, Cullen Kafka and Brett Walker while adding Tyler Frazier to the mix when the Ducks host Fresno State in a four-game nonconference series beginning at 6 p.m. Thursday at PK Park. Those four pitchers combined to allow three earned runs in 23 innings last week.

“Our starting pitching consistently threw more strikes than we have been from top to bottom,” Horton said. “Any time you sweep an opponent in the Pac it is successful so we will take it and hopefully build some momentum.”

Oregon’s pitchers have adjusted roles all season due to injuries to three starting pitchers and unpredictability from the bullpen.

Junior Kenyon Yovan, a two-time all-conference pitcher, has not thrown since the opener Feb. 15 due to discomfort in his hand caused by blood clots.

“He is still going through of series of tests to try and get better,” Horton said. “We don’t know how long he is out because every week that he is not throwing means we have to build him back up. We are trying to get second opinions on him and see where that goes.”

Junior Ryne Nelson, also considered a likely early-round pick in the June draft, has pitched in relief for the past four weeks following a heel injury. He earned a save last week at Utah Valley and picked up a win at Utah.

“We are still using Nellie as a wild card so when we see an opportunity to get a game, we use him,” Horton explained.

Cole Stringer missed three weeks due to injury before returning to pitch an inning of relief at Utah.

“We underdid it with him for one inning and the results were very good,” Horton said. “That will be another weekend to build him up and get him back in the mix.”

Stringer and Nelson will likely be back in the bullpen for the Ducks (16-10) when Horton goes with a youthful starting staff against the Bulldogs (13-9).

Frazier, a freshman right-hander, will make his second straight start in the opener followed by Ahlstrom on Friday. The sophomore left-hander from North Eugene High School has allowed two earned runs in 14 innings during his last three appearances while striking out 17.

“I have been bouncing around roles, but I started most of my life so I am comfortable with that routine,” Ahlstrom said. “We have definitely had bad luck in terms of injuries, but everyone has done a good job stepping up. You never know when your name will be called for a certain role so I try to make the most of my opportunities."

Kafka will make his team-leading eighth start Saturday while Walker likely starts the series finale.

The Ducks have scored 36 runs during a four-game winning streak.

“Our hitters from top to bottom have done a great job getting in the box and putting together quality at-bats,” said freshman outfielder Tanner Smith, who is batting .316 after going 7-for-12 in three wins over the Utes. “We string stuff together well even with two outs and find a way to add one or two runs when needed toward the end of the game.”

The Ducks were without catcher Jakob Goldfarb last week due to an ankle injury.

“We are still not at full strength,” Horton noted. “I think this Fresno State series is good because we can plays some guys who have not been given a lot of opportunities and sharpen them up and hopefully still be successful in terms of wins and losses as we move on.”

Oregon is tied for fifth in the Pac-12 at 5-4 as it prepares for five straight nonconference games, including a trip to seventh-ranked Oregon State on Tuesday before returning to conference play at Washington State.

“We’ve got a lot of good chemistry going on right now,” Ahlstrom said. “This is a nonconference weekend, but still important games to get ready for Washington State.”