Things are about to get more crowded.

September is here. Rosters have expanded. Every manager has new toys to play with, and some are more eager to use them than others.

It makes dabbling in sleepers a risky approach this time of year. Obviously, the most-owned hitters are fixtures in their teams' lineups, but the kind we recommend here may be looking over their shoulder the rest of the way. Some of them, anyway.

So you'll want to use extra caution when setting your lineups -- especially this week, when the new usage patterns are only now being revealed. If you have an opening, great. These 10 hitters owned in less than 80 percent of CBS Sports leagues are one way to fill it. But you wouldn't want to take any unnecessary risks.

Sleeper hitters for Week 23
Scooter Gennett Cincinnati Reds 2B
I'm a little surprised Scooter Gennett still qualifies for this list seeing as he's eligible at three positions and has an .840 OPS over the past two months (which obviously doesn't include his four-homer game in June). He should do some of his best work with right-handers like Seth Lugo, Chris Flexen and Rafael Montero on the schedule. Overall, he's batting .306 with a .941 OPS against righties, which is all the Reds face this week.
Dexter Fowler St. Louis Cardinals CF
Dexter Fowler is the best of the Cardinals hitters who fall below the 80 percent ownership threshold, so he's the one I'm targeting for the matchups they have this week, facing the Padres rotation for four games and the Pirates (Gerrit Cole excluded) for three. He ended up hitting .328 with a 1.006 OPS in August after missing the first week with a strained forearm.
Josh Reddick Houston Astros RF
Josh Reddick is one of the top 40 outfielders in points leagues this year -- an impressive achievement considering he tends to sit against lefties. So with six righties on what's looking like one of the five most favorable schedules for the week, he's almost too obvious.
Greg Bird New York Yankees 1B
In six games since returning from a four-month absence for an ankle injury -- one that ultimately required surgery -- Greg Bird has homered twice and struck out four times, looking much more like the player who made headlines this spring than the one who was completely overmatched in April. It's probably not a coincidence he initially suffered the injury at the end of spring training. The Yankees face the Orioles and Rangers rotations this week, so he's in good shape.
Nicholas Castellanos Detroit Tigers 3B
Much of the batted-ball data suggests Nicholas Castellanos should have had more success than he has this year, but he hasn't come up short against left-handers, batting .275 with 11 homers and a .937 OPS in 120 at-bats. The Tigers have three on the schedule this week, just when Castellanos is beginning to heat up with a .342 batting average and .954 OPS in his last 17 games.
Eddie Rosario Minnesota Twins LF
Since June 13 -- a span of 68 games -- Eddie Rosario is batting .325 with 15 homers and a .954 OPS, making him the 13th-best outfielder in points leagues and the eighth-best in categories during that stretch, so I have hard time turning away from him when the Twins matchups are anything better than miserable. I'm not particular intimidated by Jake Odorizzi, Eric Skoglund, Ian Kennedy and Jason Vargas. Are you?
Kolten Wong St. Louis Cardinals 2B
I already pointed out that the Cardinals have some of the best matchups of any team this week, but I didn't point out one of the more available players who could take advantage. At 29 percent ownership, Kolten Wong is almost universally available in mixed leagues, and he just hit .347 with a .958 OPS in August. His power mostly manifests as doubles, and one of his greatest strengths is simply making consistent contact. Still, a second base version of Gerardo Parra would be useful to many.
Scott Schebler Cincinnati Reds RF
Scott Schebler has been hot since returning from a strained rotator cuff Aug. 18, batting .351 (13 for 37) with three homers in 12 games, and having nothing but righties on the schedule should ensure he sticks in the lineup even with rosters expanded. He has actually had more success against lefties than righties this year, but that's not the norm for him and not a split the Reds seem to honor. The matchups against the Brewers and Mets pitching staffs should help.
Asdrubal Cabrera New York Mets SS
Asdrubal Cabrera is one of the last veterans standing after all the trades the Mets have made the last two months, so his job security might be better than ever. He's making the most of it, too, batting .348 (8 for 23) over his last seven games, and it just so happens the Mets have the best matchups of any team this week, going against the Phillies and Reds pitching staffs.
Dominic Smith New York Mets 1B
Going out on a limb here for a 22-year-old off to an 11-for-67 (.164), but you may have heard the Mets have terrific matchups this week. You may not have heard they're facing all righties, which is notable because, at Triple-A Las Vegas, Dominic Smith hit .353 with a .951 OPS against righties this year compared to .247 with a .733 OPS against lefties. And though he has yet to find much success against any type of pitcher at the big-league level, he has struck out less than one every five at-bats against righties. Consider Smith your deep-league special for the week.

Best hitter matchups for Week 23

1. Mets PHI3, CIN4
2. Astros @SEA3, @OAK3
3. Cardinals @SD4, PIT3
4. Giants @COL3, @CHW3
5. Indians @CHW4, BAL3

Worst hitter matchups for Week 23

1. Padres STL4, @ARI3
2. Pirates CHC4, @STL3
3. Rockies SF3, @LAD4
4. Brewers @CIN3, @CHC3
5. Rays MIN3, @BOS3