The top pitcher is expected to miss Friday’s season opener.

The most experienced catcher will be unavailable for up to six weeks.

And a productive second baseman will not play at all this season.

So why is Hawaii baseball coach Mike Trapasso so optimistic about his 18th season with the Rainbow Warriors?

“I have high expectations because of our kids,” Trapasso said. “I have high expectations because of the job our staff has done and continues to do on a daily basis.”

Dylan Thomas, who is making the transition from elite closer to ace, is likely to be held out until he is fully cured from the blister problem on the index finger of his right (pitching) hand. Three true freshmen — Aaron Davenport, Cade Halemanu and Blaze Pontes — will get work this weekend while pitching roles are being defined. Trapasso said he is hopeful “about the number of guys who are capable” of pitching.

On Tuesday, catcher Tyler Murray underwent surgery to repair the hamate bone in his left wrist. In Murray’s absence, freshman Dallas Duarte will ascend to primary catcher.

Second baseman Dustin Demeter underwent two operations for a hip-related injuries. This weekend, newcomer Jack Kennelly will play second. As a Bellevue (Wash.) College freshman in 2017, Kennelly won a Golden Glove as one of junior colleges’ top-fielding infielders.

“We’ve had adversity even before we’ve encountered our first pitch,” Trapasso said of the medical list, which also includes reliever Kyle Hatton’s season-ending injury. “But this is a team that’s deep enough and mature enough to handle that.”

In fall and winter training, the ’Bows have shown to be a reliable defensive team. Each year, Trapasso said, the goal is to field at .975.

“I don’t feel there’s a reason we can’t field at .980, which puts you in the top 10 to 15 in the country in fielding percentage,” Trapasso said. “We have to take care of the baseball. Physical errors are going to happen. But the difference between .970 and .975 is just taking care of the baseball and not making unnecessary risky throws. You’re going to boot balls. You’re going to throw some away. It’s when you make errors by rushing, by not having your feet underneath you, by being careless, that’s where the maturity of our defensive group, our infield, should come into play.”

PITCHERS

After amassing a Big West-leading 14 saves last season, Dylan Thomas had little trouble moving to the front of the rotation. Thomas’ out pitch has been a slider that he can manipulate into breaking to either side of the plate by shifting his grip’s pressure point. But he also added a change-up, which complements the slider. Thomas is expected to miss the opening series after developing a blister on the index finger.

If Thomas is unavailable, left-handed Jeremy Wu-Yelland will start on Friday. Since high school, the book on Wu-Yelland is he has a violent fastball with oomph (up to 95 mph) but not accuracy. In fall training, Wu-Yelland shortened the motion from pulling the ball out of the glove to the launch position. Picture the motion as pulling back a gun’s trigger. By hastening the motion to the backside, it allowed Wu-Yelland an easier flow — and better control. Trapasso said Wu-Yelland, who also throws a power slider, has been dominant in recent scrimmages.

Freshman Aaron Davenport and senior Dominic DeMiero have earned starting jobs. In scrimmages, Davenport attacked the zone with a 92-mph fastball and a so-called 12-6 (o’clock) curveball. DeMiero, who endured shoulder tendinitis near the end of the past two seasons, has regained the command of his fastball, changeup and slider.

Cade Smith, Kash Koltermann, Cade Halemanu, Calvin Turchin and Blaze Pontes also are considerations in the starting rotation.

Trapasso said Smith has matched an improved changeup (the grip was changed) with a 92-mph fastball with a high spin rate. “There’s deception there, because the ball gets on you,” Trapasso said.

In reviewing the 2018 season, Trapasso concluded Koltermann is best suited as a starter, where he can dictate the pace.

Trapasso said Halemanu, a freshman from Pearl City, is a “strike thrower with a plus, plus changeup that is really hard for hitters to gauge.” Trapasso said Pontes improved his fastball’s velocity from mid-80s as a Kamehameha senior to 87-90 mph as a UH freshman.

Turchin is viewed as a pitcher with multiple roles. “Everything he throws moves,” Trapasso said of Turchin’s four-seamer that cuts and two-seamer that sinks. “He’s got a plus swing-and-a-miss slider as an out pitch.”

Left-hander Scott Bellina and Colin Ashworth are short-inning specialists.

CATCHERS

The Milwaukee Brewers drafted Kekai Rios. Chayce Ka‘aua and David Noworyta graduated. That left Tyler Murray as the lone returning catcher. But a wrist injury will keep Murray out of the lineup for up to six weeks. Murray hit only .213, but the pitchers were 11-6 with a 3.68 ERA in games he started.

Freshman Dallas Duarte will handle most of the catching. He fulfills Trapasso’s order of preference: receiving, blocking, throwing and hitting. “We’re very confident in Dallas,” Trapasso said. Duarte is a skilled defender who also can play second or in the outfield.

Daniel Crasnick, another true freshman, will serve as Duarte’s backup. Logan Pouelsen is another option. Pouelsen also can play first, third and pitch.

INFIELDERS

Shortstop Maaki Yamazaki, who was born and reared in Japan, was thought to be mainly a skilled fielder when he joined the ’Bows as an unscouted walk-on. “We didn’t know we had a plus-offensive shortstop,” Trapasso said. Yamazaki, who moved from ninth to top of the order, led the ’Bows in average (.409), hits (62) and runs (34). He batted .468 when leading off an inning, and struck out only once every 14.7 at-bats.

Jack Kennelly, who will open at second, was pre-judged similarly to Yamazaki. But in preseason training, Kennelly showed some offensive punch. It is believed Kennelly benefited from moving from a junior-college league that used wooden bats to using the NCAA’s aluminum bats.

In his return to the infield after a season as an outfielder, Ethan Lopez showed range and first-step quickness at third. He also provided gap power with 11 doubles and six homers. The ’Bows hope to cash in on Lopez’s hitting. Despite 17 extra-base hits, Lopez finished with only 17 RBIs. In Big West play, he had 10 extra-base hits and seven RBIs.

Alex Baeza is as good a fielder as his first-base predecessor, Eric Ramirez.

Pouelsen is the top backup at third and first.

OUTFIELDERS

The ’Bows did not have to search far for the successor to center fielder Dylan Vchulek. Adam Fogel moved from right field to center, where his speed (he once was timed at 6.6 seconds over 60 yards), range and experience are useful in the cross-winds at Les Murakami Stadium. Fogel perfected his craft in the prestigious Cape Cod League last summer. In 2018, Fogel led the ’Bows in homers (eight), RBIs (37), doubles (17), triples (two), and slugging (.526).

Scotty Scott takes over in left field and at the top of the order. Trapasso said Scott can hit to all fields, work deep into counts, and is aggressive but instinctive on the base paths.

After a two-year apprenticeship, Jacob Sniffin gets a shot as the right fielder. Sniffin has the strongest arm among the outfielders. New hitting coach Mike Brown has worked with Sniffin on going with the pitch. In preseason training, Sniffin has managed to consistently spray opposite-field shots.

“As a left-handed hitter, if you hit the ball over shortstop’s head, it counts as much as a base hit that you pull down the right-field line,” Trapasso mused. “Last year, for Jacob, hitting the ball to the opposite field was basically pulling the ball to the second baseman. He’s done a much better job.”

In last Saturday’s alumni game, Sniffin hit two inside-the-park homers.