Utah’s defense has been terrific this season, but the No. 10 Utes’ offense could use an upgrade.That revelation is from Utes quarterback Nate Johnson.Utah (4-0, 1-0 Pac-12) strives to remain unbeaten while increasing its offensive production when it battles No. 19 Oregon State (3-1, 0-1) in a Friday night Pac-12 clash at Corvallis, Ore.Star quarterback Cam Rising hasn’t played since tearing his left anterior cruciate ligament during the Utes’ Jan. 2 Rose Bowl loss to Penn State. Rising has been sharing time with Johnson in practice but has yet to be cleared for game duty.Bryson Barnes and Johnson split time the first two games before Johnson became the starter for the past two. However, Johnson wasn’t the least bit happy with the meager 219 yards of total offense the Utes compiled during a 14-7 home victory over then-No. 22 UCLA last week.”I apologize for the way the game was played out,” Johnson wrote on social media after the contest. “Credit to our defense for an amazing performance. We will be better next week. Our offense is still awesome, just things will get cleaned up. See you guys next Friday.”Utah coach Kyle Whittingham, who doesn’t participate in social media, didn’t know of Johnson’s sentiments until Monday.”I’m completely ignorant and oblivious to what he said,” Whittingham said in a news conference. “But that’s admirable if he’s taking accountability. … I take that as a positive thing from Nate that he would point the finger at himself, even though I’m not buying into that.”Johnson connected on 9 of 17 passes for 117 yards and one touchdown against UCLA.The Utes’ defense controlled the contest while holding the Bruins to nine net rushing yards and 243 total yards. Standout defensive end Jonah Elliss, the son of former Utah All-American Luther Elliss, established career highs for tackles (10), tackles for loss (five) and sacks (3.5).Utah is tied for ninth nationally in total defense (263.8 yards per game), ranks sixth in scoring defense (9.5 points per game) and is third in rushing defense (51 yards per game).Oregon State also is looking for improved quarterback play after DJ Uiagalelei completed half his 34 passes for 198 yards, one touchdown and one interception in a 38-35 road loss at then-No. 21 Washington State last week.