DENVER -- Two big bats that have been out of commission for Colorado much of the summer are a step closer to rejoining the club. Troy Tulowitzki and Jason Giambi were each set to play their third rehab game with the Double-A Tulsa Drillers Monday night and could be activated as early as Saturday.

"The plan moving forward is for them to play tonight," Rockies manager Jim Tracy said before Monday's series opener against the Dodgers. "They'll be here in Denver tomorrow to be re-evaluated physically and see how they're doing. If everything checks out, then the plan moving forward would be to send them to [Triple-A] Colorado Springs on Wednesday and play a couple days there."

Tulowitzki has been recovering from groin surgery since May 30, and Giambi has been on the DL with a viral infection since July 21. In two games each in Double-A, Tulo is 1-for-6 with a double and an RBI, and Giambi is 1-for-4 with an RBI.

With the 25-man rosters expanding to as many as 40 on Saturday, both players will probably wait until at least that date to avoid additional roster moves.

"I think there's a strong likelihood that we would not do anything prior to Saturday, but I can't sit here and say definitely that Saturday is the target date for either one of those two guys," Tracy said. "At some point in time I am very hopeful of that."

Tulowitzki has missed 77 games heading into Monday, and the chance to return for a full September is valuable on a couple of fronts.

"Peace of mind as far as Tulo's concerned, so that between now and the fourth of October, he goes home knowing that everything's OK, that hopefully he gets a good feel physically as to where he's at, that he knows everything's in place," Tracy said.

A second reason is that, in Tulowitzki's absence, Josh Rutledge has emerged as a top rookie shortstop, hitting .338 with seven homers and 25 RBIs in 37 games. He's already penciled in as the Rockies' second baseman of the future, and the Rockies are eager to see Tulowitzki and Rutledge together on the big league stage this season.

"The opportunity to play together in the middle [of the infield] instead of it being in a less stressful environment beginning in Spring Training, it's much more important that we get them involved out here in Major League game-type situations, which -- fingers crossed -- hopefully we'll have an opportunity to do," Tracy said.

Rutledge has been nursing a tight quad and has been limited to pinch-hit appearances of late. He is available for a double-switch situation Monday.

LeMahieu has improved each month with Rox

DENVER -- In a season marked by Rockies rookies excelling all around the diamond, second baseman DJ LeMahieu has made a big impression.

After coming with Tyler Colvin in the trade that sent Ian Stewart to the Cubs this offseason, LeMahieu has gotten better and better. He played 37 games and hit .250 in his big league debut with the Cubs last year, but he is hitting .288 in 49 games with the Rockies this season. He started out hitting .200 (2-for-10) in May, and has improved month-by-month, hitting .207 (6-for-29) in June, .316 (6-for-19) in July and .328 (22-for-67) in August.

"He has a real nose for the ball," Rockies manager Jim Tracy said before opening a series against the Dodgers on Monday. "His field awareness is off the charts. He's a very good situational hitter. He has improved offensively, evidenced again yesterday by the double that he hit when he drove the ball over the center fielder's head."

LeMahieu has been working on making a mechanical adjustment at the plate, working to fire his lower half to get the bat a little further forward.

"That's what we're spending time on right now," Tracy said. "I personally feel we're succeeding. It's not an overnight fix. I knew that it wouldn't be. This is something from an offensive standpoint -- a project that we started with him on back in December -- and he's slowly but surely gravitating toward the area that we want him to go in."

LeMahieu figures to be a big part of the Rockies' infield plans, though he's probably penciled in behind Josh Rutledge at second, Troy Tulowitzki at short and Jordan Pacheco at third for the 2013 season.

"There's nothing not to like about this player," Tracy said. "He's versatile, he's smart, he's a gamer. Everything to love."

Fowler again limited to pinch-hit duties

DENVER -- In Monday's series opener against the Dodgers, Dexter Fowler missed his fifth start since rolling his ankle running the bases in Wednesday's win against the Mets in New York. He pinch-hit Saturday and Sunday against the Cubs in Chicago, and is not yet ready to play the field.

"I'd have to say [he's available for] nothing beyond what he's done the last couple days," Rockies manager Jim Tracy said. "The fly ball that he hit leading off the top of the sixth inning [Sunday], coming out of the box and moving to first base, he was very ginger on that ankle."

Fowler has a career year in the works, hitting .305 with 12 home runs, 44 RBIs and a league-best 11 triples.

"I don't think right now that we have a major issue moving forward, straight ahead, but cutting and quick jab steps, routes that would be taken in the outfield, those type of things, those are still issues," Tracy said. "If a ball were to come out to him where he'd have to dive in order to make a play or something like that, we'd still have issues."

Worth noting

When Jeff Francis toed the rubber at Coors Field on Monday night, he faced a familiar foe. Josh Becket was Francis' opposing pitcher in Game 1 of the 2007 World Series, a game the Red Sox won, 13-1.

Beckett isn't the only new face wearing Dodger Blue this series. The Dodgers acquired Beckett, first baseman Adrian Gonzalez, outfielder Carl Crawford (disabled list) and infielder Nick Punto on Saturday from the Red Sox. Left fielder Shane Victorino, shortstop Hanley Ramirez, Wednesday's starting pitcher Joe Blanton, and relievers Randy Choate and Brandon League have all recently been required.

"It is a big deal," Rockies manager Jim Tracy said of the Dodgers' trade with Boston. "They acquired significant players in the deal. They deepened themselves if it plays out. It makes them very formidable.

"It's a terrific challenge for our young players to go out there and play against a group like this one. I think in relation to what I've seen over the last three weeks, our guys will embrace this challenge."