CHICAGO -- Josh Vitters wasn't in Sunday's starting lineup for the Cubs' series finale against the Reds, but manager Dale Sveum said the rookie third baseman likely will start at least twice in Chicago's upcoming series against the Astros.

Vitters, the club's first-round Draft pick (No. 3 overall) in 2007, has appeared in six games, with three starts. He has two hits in 16 at-bats (.125), one of which was a pinch-hit, two-run double on Aug. 7 against San Diego.

Although the 22-year-old hasn't taken to the Majors quickly, offense is the one thing that has rarely been a question with Vitters. He was a .283 hitter in the Minor Leagues, and he was hitting .304 with 17 home runs an 68 RBIs at Triple-A Iowa before being promoted.

Sveum said he eventually sees Vitters maturing into a player "capable of hitting 20 home runs if he plays every day -- easily 20 home runs.

"His swing should definitely play in the big leagues," Sveum said. "His hands are very live. He's a great fastball hitter, and great fastball hitters usually survive and do well at this level."

Defensively, Vitters is still a work in progress. He's committed one error -- which came Friday on a hard one-hopper that would be a tough play for many players -- but he has also made a couple of impressive stops. Sveum said he already sees improvement when watching Vitters take ground balls, but he's interested to see how that growth translates to game situations.

"That's going to be the evaluation in the next 50 games, however many he plays, the exposure," Sveum said. "This is a lot of evaluation, and we'll see where we're at as soon as he's getting more exposed with game-time ground balls and everything."

Russell churning out appearances for Cubs

CHICAGO -- Cubs left-hander James Russell has been one of the hardest-working relievers in baseball this season, entering Sunday with 56 appearances.

Russell is tied with Mets lefty Tim Byrdak for the second-most appearances in the Majors, one behind teammate Shawn Camp and Houston's Wesley Wright.

Russell took the loss Saturday -- his first of the year -- when he allowed two runs on five hits in the eighth inning of the Cubs' 4-2 loss to the Reds. Despite the defeat and a high workload this year, Russell said he's feeling fine as the season heads into mid-August.

"Body feels great," Russell said. "There's no sign of me getting dragged down. My body feels great, physically."

Russell, 26, is in his third Major League season. He's nearing his career high in appearance (64) and innings (67 2/3), both of which were set last year.

The reason for the added work is simple: Russell is putting together the best season of his career, posting his lowest ERA (3.59) while allowing fewer home runs -- five compared to double-digits the past two seasons.

Russell is also only two shy of his career high in strikeouts, although he's already issued a career-high 19 walks.

Worth noting

• Center fielder Brett Jackson returned to the starting lineup for Sunday's finale with the Reds, hitting seventh. Jackson sat Saturday after an outfield collision in Friday's game.

"He took swings and he's a lot, lot better today," Sveum said.

• Outfield prospect Jorge Soler hit his first home run, a grand slam, for Class A Peoria on Saturday.

• Right-hander Casey Coleman, currently at Triple-A Iowa, will not pitch for several days because of back shoulder soreness. He will be re-evaluated before it is determined when he will return to the mound.