CINCINNATI -- Entering the finale of a four-game series Thursday, the D-backs are in the heart of a 20-day stretch of games.

After three on the road in Chicago and four in Cincinnati, Arizona heads home for 10 straight games before visiting the West Coast for a final three-game set against the Dodgers.

The D-backs have to wait until Aug. 2 to get their first off-day since the All-Star break.

"There's an expense of hurting somebody and their performance, I think it wanes as well," said manager Kirk Gibson, who has used a different lineup in each game in Cincinnati. "Normally, I would be more matchup-oriented, but you just have to do it."

With the risk of injury always threatening, Gibson said the staff keeps a close eye on the team's energy levels during stretches like these.

For example, both Miguel Montero and Stephen Drew had started all six games since the break. It was the first time all season Drew had played six consecutive days, and Gibson gave his shortstop a day off Thursday. Willie Bloomquist got the nod at short. Montero also got a break, with Henry Blanco starting behind the plate.

"You just kind of read their exertion levels and kind of read their bodies," Gibson said. "You see them in [the clubhouse] and follow them around for training activities, weight room activities and see how hot the game is. You just kind of take it all into consideration."

While the normal rigors of the schedule can take a toll on a player's body, right fielder Justin Upton said the 20-day stretch can be especially grueling.

Among games, workouts and traveling, Upton said the key to staying physically and mentally sharp is to conserve energy whenever possible.

"I think it's just being smart with your work load before the game and try to stay as fresh as possible," Upton said. "You're making sure you get your work in, but don't exert yourself too much and try to preserve your energy. Just being smart throughout the stretch is probably the biggest thing."

Upton, who has played in 85 of the club's 91 games entering Thursday, said he rests when he gets the chance.

"You make sure you get your sleep," he said. "Don't try to do too much and just kind of weather the storm."

Collmenter back in rotation, at least for now

CINCINNATI -- Josh Collmenter can basically do it all.

The 26-year-old righty has made appearances this season as a starter, a long reliever and short reliever for the D-backs, and has taken it all in stride.

"Collmenter has the ability to understand what his role is for that day and he just prepares for that," said manager Kirk Gibson. "If we asked him to just get up and get ready for the next hitter, he could do it, in my mind. If Joe Saunders can't make his start and [Collmenter's] got 10 minutes to warm up, he just does it."

With the recent decision to send young Trevor Bauer back to Triple-A Reno for some mechanical tweaking, Gibson chose Collmenter to return to the rotation -- for now.

Collmenter has 18 appearances, including seven starts. Even with Collmenter slated to start Sunday against Houston, Gibson said the righty could make an appearance out of the bullpen if the situation called for it.

"Right now, Collmenter is our long guy in all reality, but he's scheduled to pitch Sunday," Gibson said. "If we really got in a bind, he wouldn't be an early long guy right now like he'd normally be, but if we got into a really extended game, I'd use him if we needed an extra pitcher. But right now, our bullpen is very rested and in good shape."

"Good shape" may be an understatement.

Arizona's 1.88 bullpen ERA since June 22 is the best in the National League, and Collmenter has been a large contributor, posting a 1-0 record with a 1.30 ERA since May.

Gibson described his second-year pitcher as "very versatile," and said Collmenter has filled every role the club has asked and it was "not even an issue."

"Watch some relievers around the league and the different things that they do when they get up to throw the ball. Some guys put gum in their mouth, some guys put tobacco in, some guys tie their shoes, some guys stretch a little bit. Collmenter, it's just his time to go."

McDonald, Saito getting closer to returning

CINCINNATI -- Arizona continues to hear good news from its recovering players, as shortstop John McDonald and pitcher Takashi Saito make steps toward a Major League return.

McDonald was placed on the 15-day disabled list on July 2, retroactive to June 25, nursing a slight strain of his left oblique, which he thought was suffered in Kansas City in mid-May.

He continues to work out at Salt River Fields in Arizona, and D-backs manager Kirk Gibson said he may return to action as soon as Friday night.

"I talked to [McDonald] on the phone [Wednesday] and he feels better," Gibson said. "I think he's maybe going to play in the game tonight [in the Arizona League]."

McDonald did face a minor hiccup on his road to recovery, catching bronchitis during the All-Star break.

Gibson said the veteran shortstop is almost over the throat illness.

"I talked to him [Wednesday] and he was doing quite a bit of coughing," Gibson said. "He hasn't felt great. We'll see when he gets in the game how he feels."

Saito, who has yet to make an appearance with Arizona, has been out with a right calf strain and a respiratory illness.

He threw one scoreless inning with two strikeouts against the Arizona League Brewers on Tuesday, and will join McDonald in Salt River Fields for workouts.

"He's been throwing the ball much better and throwing more of his secondary pitches," Gibson said. "I sense he's feeling much more comfortable than he has all year."

Worth noting

• Among all National League second basemen, Aaron Hill entered Thursday's game leading the league in slugging percentage (.501), batting average (.299), and hits (100), ranking second in on-base percentage (.353) and doubles (22).