MESA, Ariz. — Most bullpen sessions this week at Cubs camp have been brief: about 15 minutes, fire off some pitches and then the pitcher is done.

Shota Imanaga’s bullpen at the 12-pack bullpen area at Sloan Park was different.

Imanaga was still pitching when the rest of his bullpen group — Julian Merryweather and Trevor Richards — had wrapped up.

“He threw 45ish pitches, so there’s a little more volume,” manager Craig Counsell said on Wednesday. “We’re just trying to build up the volume.”

This spring is a touch different for Imanaga and the Cubs. Last season, the two sides worked more on familiarity and trying to tone things down for a pitcher with a rolodex of pitches in his arsenal.

[WATCH: Shota Imanaga ready to see how Cubs adjust to playing in Japan]

“Last year we were going through, frankly, some simplification of things,” Counsell said. “And really kind of from our side, just like building confidence for him in how good his fastball is.

“We had obviously numbers on it, and we thought it was just a great pitch, and just making sure we knew how good the pitch was and how much hitters were going to struggle.”

The pitch was his bread and butter all year. He threw it 52% of the time and opponents hit .229 against it. The ride on his fastball played perfectly with his splitter, which dove away hitters as it reached home plate. Hitters mustered a .204 batting average against that breaking ball.

This year, Imanaga and the Cubs can work more on the physical side and ramping up for Opening Day — which is a little over a month away.

“At this point, these guys are just trying to get comfortable in their deliveries or something,” Counsell said. “They’re trying to have their arms get tired and recover. That’s the main focus on days like today.”

Middle infield injury updates

Dansby Swanson and Nico Hoerner were the backbone of the Cubs’ defense. The shortstop and second baseman both underwent offseason surgery — Swanson to address a sports hernia in early October and Hoerner a flexor tendon operation in October as well.

Swanson has been working out at Sloan Park ahead of full squad report day on Friday. He doesn’t have limitations, but the Cubs aren’t pushing him, either.

“I think we’ll probably be a little careful just with his ramp up,” Counsell said. “Just want him to run around out here a couple extra days as he kind of ramps up intensity.”

Hoerner — who had said at Cubs Convention last month that he hadn’t begun to hit — is hitting soft toss right now and in a throwing progression. That will be the most important area in his recovery.

“Right now, we have to be very disciplined about his throwing. He’s still in a throwing program,” Counsell said. “He’s in an arm strength kind of progression back from surgery program. So that’s kind of where we’re at.”

New digs

Eli Morgan — acquired in a trade from Cleveland for prospect Alfonsin Rosario — threw a bullpen session at the 12-pack on Wednesday. It was his first appearance in his new threads since camp opened.