MILWAUKEE -- The Reds are doing all that they can to hang on in the National League Central and NL Wild Card races with one week to go before the July 31 Trade Deadline. They could have done without the developments that befell them Wednesday afternoon during a 5-4 loss to the Brewers that prevented a three-game series sweep.

Rookie center fielder Nick Senzel had to leave the game when he didn’t feel well, and Juan Graterol became the latest Reds catcher to get banged up.

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Everything looked completely normal at first when Senzel got the game going on a good note for Cincinnati with a single lined into right field on a full-count pitch from Jhoulys Chacin. Senzel reached first base without issue and fist-bumped first-base coach Delino DeShields. Then he appeared to struggle.

Head trainer Steve Baumann and manager David Bell came out to see Senzel, who had to leave the game. It was later termed that “illness” was the reason that he exited, but the hope is that more isn’t involved.

“I'm just ill. I don't feel very good,” Senzel said. “First pitch I swung at, I just got dizzy. I had to take my time and it didn't get any better.”

Feeling dizzy is no small matter for Senzel, who missed a month last season with Triple-A Louisville because of vertigo, an inner-ear condition that can cause a loss of balance and dizzy spells.

Senzel was asked if he was dealing with a similar problem Wednesday.

“I don't know,” he replied.

The former No. 1 prospect in the organization, Senzel has been a boost to the Reds since he made his Major League debut on May 3. Through 66 games, mostly in the leadoff spot, he is batting .277/.342/.466 with eight home runs and 29 RBIs. He was batting .361 (13-for-36) since the All-Star break.

“He just wasn’t feeling well,” Bell said. “That was the first we knew of it when he got to first base. He wasn’t feeling well during his at-bat. After running to first, he couldn’t stay in there.”

Phillip Ervin replaced Senzel as a pinch-runner and took over in center field. Ervin scored the game’s first run on Josh VanMeter’s RBI single, and he notched two hits of his own. Ervin scored another run on Joey Votto’s RBI single in the second inning.

Graterol was called up July 17 when Cincinnati lost catchers Curt Casali (right knee) and Kyle Farmer (concussion) to the injured list. The club was already without Tucker Barnhart (right oblique), who has been on the IL since June 28.

In the third inning, Graterol took a pair of foul balls off his face mask in a short span of time. The second ball, from the bat of Lorenzo Cain, knocked his mask off and left him not feeling right. Graterol came out of the game and Ryan Lavarnway -- who was just signed Thursday -- took over behind the plate.

“We're going to keep an eye on him and make sure it's nothing serious,” Bell said. “It was enough, given all that's gone on, to get him out of there … the second one just him more in the jaw. It would have to be super convincing to leave him in there. I was pretty cautious getting him out."

While Casali is expected to be out until sometime in August, the Reds could be in a bind if Graterol has to miss time. Barnhart was scheduled to begin a rehab assignment at Triple-A Louisville on Thursday, while Farmer was slated to be re-examined by a doctor with the hope that he could be cleared for a rehab assignment.

At Triple-A, Cincinnati has Chadwick Tromp and Stuart Turner -- neither of whom is on the 40-man roster. At Double-A Chattanooga, there is Tyler Stephenson, who is the organization’s No. 5 prospect.

Adding some hot sauce to the eye for the Reds is that the Cubs beat the Giants on Wednesday. That moved Cincinnati back to eight games out of first place in the NL Central. The Reds would still like to make some additions to the bullpen and offense over the next week. But Wednesday’s developments could certainly have the front office scouring for other additions.