"They need game time," farm director Reid Nichols said.
Brewers officials have seen Arcia, who played for the club's Dominican Summer League affiliate in 2011, but have yet to really get their hands on Roache, a power hitter who belted 30 home runs for Georgia Southern University in 2011 but suffered a major left arm injury diving for a ball in the outfield in February. He had six screws and a metal plate installed to repair a broken bone, and two pins to fix a dislocated wrist.
"We're anxious to see him because he's been given the full clearance, and I know he's excited," amateur scouting director Bruce Seid said. "I know he's been champing at the bit for a while to get out there, and he's been great about doing every single thing that ask of him. To this point, every evaluation from our medical staff has been right on."
Nichols runs the Brewers' fall program at Maryvale Baseball Park with assistant player development director Tony Diggs and a slew of roving Minor League coordinators, including field and catching coordinator Charlie Greene. Ned Yost IV, the son of the former Brewers manager who is now a coach at advanced Class A Brevard County, will manage the team.
Thirty-eight players were on the initial roster, including the Brewers' first nine selections from the 2012 First-Year Player Draft -- from top pick Clint Coulter through seventh-rounder David Otterman, a left-handed pitcher.
Coulter will work extensively with Greene on catching fundamentals. The Brewers remain committed to developing him at that position, Nichols said.
"He came a long way this year," he said. "To ask a high school guy who played 14 games to step into a pro program and handle college pitchers is a tall order for him. He's really improved. He's going to be a good player."
The instructional league will mark a return to action for supplemental first-round pick Mitch Haniger, who missed much of the season with a knee injury but is close to being cleared to play.
Also on the roster are 2011 second-round pick Jorge Lopez, a right-hander, and international acquisition Raul Mondesi Jr., an outfielder who played at rookie-level Helena in 2012.
"We prepare them ahead of time that, you're coming here to work," Nichols said. "So what we do is we give them one day that's a full work day, then the next that's a game day. So when they know it's their day to work, they can leave everything out there, don't save anything for the game."
Work begins as early as 7:30 a.m. for some players, and the games are six days a week in the early afternoon, from Tuesday against the Padres through Oct. 4-5 against a team from Mexico.
There is also an advanced instructional league, in which the Brewers and Mariners share a club. It features more advanced prospects like pitchers Drew Gagnon and David Goforth, who stay ready in case the Brewers need a replacement for the Arizona Fall League.
If that's not enough baseball, there is another instructional league in the Dominican Republic that runs into December. The Brewers may ask Roache and Arcia to head south to continue playing catch-up.