Never stop tweaking those lineups, people. Even a first-place fantasy roster can probably use a boost somewhere. Here are six potential pickups, available in a majority of Yahoo leagues, fully approved for starting or stashing.

TJ Friedl, OF, Cincinnati Reds (17% rostered)

Of late, the Reds are never not winning and Friedl has been a significant contributor to the team's surge. He's a little platoony, sure, but that's a simple enough issue to manage around. Friedl is leading off for the hottest club in baseball, hitting .320 with 19 extra-base hits and eight steals over 52 games. He's also getting himself on base at a .380 clip and piling up runs. Last year, splitting his time between Louisville and the majors, Friedl hit 16 homers and swiped 17 bags. He's a solid multi-category fantasy option and a cheap way to get a share of a raging party of a team.

Geraldo Perdomo, 2B/3B/SS, Arizona Diamondbacks (42%)

After just 61 games, Perdomo has already equaled last season's totals in homers (5) and steals (9) while slashing .297/.406/.462. That sort of production should play in most leagues, particularly when delivered by a guy with eligibility at three roster spots. The 23-year-old's career minor league OBP was .397, so his on-base ability is well-established. Perdomo has a pair of 20-steal seasons in his minor league past, too.

David Hamilton, 2B/SS, Boston Red Sox (4%)

All you need to know about the 25-year-old Hamilton is that he'd hit 11 bombs and stolen 27 bases at Triple-A prior to his call-up. Last season, he swiped 70 bags in 78 attempts at Double-A. Basically, whenever Hamilton is in the lineup, he's a good bet to steal a base (or three). If you're in search of speed, this is your pickup.

Sal Frelick, OF, Milwaukee Brewers (6%)

Milwaukee ranks dead-last in the National League in run scoring, yet the team is still somehow above .500 and very much alive in the division race. Frelick can definitely help the cause. He returned from a thumb injury two weeks ago and hasn't stopped hitting since he rejoined Nashville's lineup:

Last year, Frelick slashed .331/.403/.480 across three minor league levels, hitting 11 homers and stealing 24 bases. He managed to improve his performance at each stop, too, eventually hitting .365/.435/.508 at Triple-A, where he walked more frequently than he struck out. It isn't difficult to imagine how he might be able to help the big league club right now.

Kyle Bradish, SP, Baltimore Orioles (18%)

He's been slider-ing hitters into submission in recent starts, punching out 19 while issuing only three walks over his last 17.0 innings. After a bumpy start to his season, he's lowered his ERA to 3.88. Batters have hammered his 4-seam fastball all year, but his slider and curve have been exceptional.

Bradish is lined up for two starts next week, so this is an ideal moment to give him a test drive.

Adbert Alzolay, RP, Chicago Cubs (34%)

It seems kinda weird that a closer with near-spotless ratios (1.91 ERA, 0.85 WHIP) is just sitting out there unattached in two-thirds of Yahoo fantasy leagues, but here we are. It's been over a month since Alzolay allowed a run. He should be scooped up pretty much everywhere.