The Houston Astros find themselves in an unfamiliar position. Long derided as the "Lastros," the franchise is sitting in first place, not just in the AL West, but in the entire American League. Credit the always-excellent Jose Altuve, some improved production from the offense as a whole, a top-notch performance by the bullpen and the work of ace Dallas Keuchel and No. 2 Collin McHugh, who are a combined 11-1.

The biggest hole on the potential playoff contender remains back of the rotation, where Roberto Hernandez, Scott Feldman and a collection of fifth starters that includes Asher Wojciechowski, Sam Deduno and others have yet to live up to the success of the rest of the team.

With many calling for a quick promotion of top shortstop prospect Carlos Correa, the Astros have exercised patience with the exciting infielder. However, they made a less heralded but more important addition from the minors ranks this week, promoting Lance McCullers Jr. from Double-A Corpus Christi.

McCullers was considered a top-50 prospect by Baseball America prior to 2013 and made it back onto the top-100 list before the 2014 season, but he struggled with his control that year en route to a 5.47 ERA and 115:56 K:BB ratio in 97 innings with high Class A Lancaster. Despite those struggles, the team still started McCullers, who by this point wasn't on many top-prospect lists, at Double-A this year. The results were excellent: 0.62 ERA, 43 strikeouts and just 11 walks in 29 innings.

With the major-league team appearing to be in serious contention, the "Firstros" have made the move to skip McCullers over Triple-A to give the back of the rotation a needed boost. His major-league debut came Monday, and though he surrendered just one earned run, he was removed after throwing 93 pitches without completing the fifth inning. He walked three in that debut, and I believe the walks will continue to be an issue this season, but he has enough upside that fantasy owners are buying in droves, with McCullers going from owned in three percent of CBSSports.com leagues to enjoying 57 percent ownership this week.

He's a must-add in dynasty leagues and a matchup weapon in redraft leagues at this point, but he's certainly worth owning over many fringe roster candidates due to his upside.

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Maikel Franco, 3B, PHI (+26 percent owned). I covered Franco last week, saying that his impending promotion would likely cause his ownership numbers to spike. As expected, he's been the most added position player and second overall only to McCullers. The third baseman has certainly encouraged belief early on, hitting .292/.346/.542 with one home run and five RBI in 24 at-bats. The third base position has been pretty deep this year, but he warrants a spot in all dynasty leagues and even consideration as a corner infielder in standard leagues.

Delino DeShields Jr., OF, TEX (+25 percent). DeShields has been a better version of Billy Hamilton in his first exposure to the majors, because while he's stealing bases at a prodigious rate (11 in 70 plate appearances thus far), he's also drawing walks and getting on base at an excellent rate, posting a .386 OBP. I'd love him as an add in all leagues if I were sure about his playing time, as he figures to see the biggest reduction in at-bats when Josh Hamilton returns next week. However, if that turns out not to be the case, feel free to jump all over the speedster.

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Alex Colome, SP, TB (-26 percent). I featured Colome in this column a few weeks ago after his first few starts, encouraging fantasy owners to snap him up, as I did in my dynasty league. For that, I apologize. After giving up eight earned runs in six innings in his third start, the pitcher allowed three runs but lasted just 3 1/3 innings in his most recent outing. I cut him for McCullers after news broke that the Astros prospect was being promoted, but I'm still keeping an eye on him hoping he gets things turned around.

Anthony DeSclafani, SP, CIN (-24 percent). DeSclafani put together three excellent starts at the beginning of the season, causing many to hop aboard for the ride. After giving up four unearned runs in his last start in April, the wheels have come off in May, as he's posted a 7.58 ERA in four starts this month. His kryptonite has been lefty swingers (.945 OPS vs. LHB, .408 OPS vs. RHB), so he's still usable in the right matchup, but the days of running him out there every week are long gone.

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Mike Wright, SP, BAL (18 percent owned). At this time last week, Wright was a fantasy unknown who was owned in zero percent of leagues. He was called upon to make a spot start Sunday with Chris Tillman and Bud Norris unavailable, and what he did put him on the map: 7 1/3 scoreless innings, four hits, no walks and six strikeouts against the Angels. He was doing well in his second year with Triple-A Norfolk before the promotion, so the numbers may not be a fluke. He's at least usable for Saturday's start against the struggling Marlins.

Jose Ramirez, SS, CLE (13 percent). With rumors swirling that Mike Aviles could soon replace Ramirez in the starting lineup, the young shortstop has finally hit his stride, going 5 for 10 with three walks in his last three games and swiping five bases in his last five. He was slotted second in each of the last three games with Carlos Santana sidelined, and Ramirez's performance could have manager Terry Francona keeping him near the top of the lineup on a regular basis. He's gone from untouchable to on-the-radar in a very short time.

Luis Sardinas, 2B/SS, MIL (3 percent). Deep-league owners looking for a short-term boost in the middle infield could do worse than Sardinas, who's filling in at shortstop with Jean Segura on the mend. Sardinas has managed at least one hit in each of his first five games while putting his great contact skills to use. He has yet to steal a base but does have two 30-steal seasons in the minors. He's a worthy flier for as long as Segura is out.