MILWAUKEE -- While Chicago fans continue to monitor the news to see if the Cubs pluck a big bullpen name from the trade-deadline market, the team's most uncertain position group is quietly taking shape.

Just a few days after the Cubs traded for powerhouse Mike Montgomery to boost the pen from the left side, Chicago will get some help from a righty. According to manager Joe Maddon, veteran Joe Nathan, who has completed a 30-day rehab assignment, will be added to the club’s roster on Sunday. A corresponding move will be announced at that time.

“He’ll be here tomorrow,” Maddon said before Saturday’s game in Milwaukee.

Nathan, 41, was signed on May 17 and immediately placed on the 60-day DL. He is coming off Tommy John surgery, performed in April 2015, and he pitched in just one game last season. But Nathan ranks eighth in big league history with 377 career saves.

In his last full season, Nathan racked up 35 saves and a 4.81 ERA over 62 appearances for the Detroit Tigers. His precise role in the Cubs’ bullpen is to be determined.

“You look at the sixth inning last night, what C.J. [Carl Edwards Jr.] did,” Maddon said. “People talk about the eighth and the ninth -- but that game was won in the sixth.

“If Joe comes up and he’s ready to roll, he’s an experienced guy who can do those kind of things earlier in the game. Or you [may] want to pop [Pedro] Strop in there earlier. We have to see what [Nathan] looks like, first of all.

“I would bet whatever he’s been throwing, it’s going to be even a little bit more when he gets here and the adrenaline gets pumping.”

The Cubs’ bullpen ERA (3.80) ranks 15th in the majors, and while it has had relatively few save opportunities overall (28), Chicago’s 64 percent conversion rate ranks 22nd. But things could be looking up.

In addition to Montgomery and Nathan, Edwards has impressed, including a sparkling effort in a key spot in Milwaukee on Friday. The emergent trio joins Hector Rondon, Travis Wood, Strop and Justin Grimm in giving Maddon perhaps his deepest group of the season.

“I do like the names,” Maddon said. “Is it enough? I think it is, but you have to consider that both Edwards and Joe, you do not want to push, push, push."

Meanwhile, the bullpen has put up a 1.35 ERA in 20 innings over its last eight games, and righty Trevor Cahill, who is on the DL with a knee injury, has begun a rehab assignment for Triple-A Iowa. Suddenly, a group that has been a sore spot for much of the season seems to be gaining traction.

Nevertheless, the Cubs continue to monitor the trade market, where big-ticket relievers such as Aroldis Chapman and Wade Davis continue to bob up on the rumor mill. The moral of the story is that when a team is pushing to win a World Series, no amount of relief pitching is too much.

“I don’t know if there’s enough yet, based on the ability to use guys, based on where they’re coming from physically,” Maddon said. “You just don’t know.

"It looks good on paper, but you’ve got to get them out there and play it.”