Of all the stars that move on every year leading up to the non-waiver Trade Deadline, few have the same impact as a No. 1 starter.
From Randy Johnson's superb stretch with the 1998 Astros to Justin Verlander's remarkable run with Houston last year, a bona fide ace can turn a fringe contender into a championship-caliber team in the blink of an eye.
The Brewers rode Carsten Sabathia's powerful left arm to a postseason berth in 2008, while Cliff Lee paid dividends for the Phillies in 2009, then again for the Rangers in 2010. Remember David Price's second-half performance for Toronto in 2015? Dominant.
Who could be this year's version of these season-altering acquisitions?
"There aren't that many good names out there," one National League general manager said.
Granted, there are still more than two months before the July 31 deadline, leaving plenty of time for teams to go into sell mode. But a quick scan of rosters around the league indicates that the biggest arms likely to be moved might not be of a race-changing caliber.
"If there are frontline starters out there, they're probably already on good teams," another NL executive said. "There does seem to be a lull in the market when it comes to frontline starters, so teams may pivot away from that."
Of the seven teams that have already lost at least 30 games this season -- a decent proxy for teams that might be "sellers" -- the most interesting names include Texas' Cole Hamels ($22.5 million salary this season; $20 million club option for 2019 with $6 million buyout), Kansas City's Danny Duffy (owed $46 million from 2019-21), San Diego's Clayton Richard ($3 million in 2019) and Tyson Ross (free agent after the season), Miami's Dan Straily and Baltimore's Kevin Gausman (two more arbitration-eligible years each beyond 2018).
Aside from Hamels, it's not the most proven group of arms we've seen heading into trade season.
"The teams that have sold have already sold those assets," an American League GM said. "Chris Sale was moved, [Jose Quintana] was moved, Verlander was moved. Before that, Johnny Cueto and Mike Leake were moved. There are guys off the second tier of teams that could become available, but sitting here in mid-May, I can't say, come hell or high water, that they will be there. Could Chris Archer be on the market? Could one of the Twins or Blue Jays pitchers be on the market? Chances are, somebody that we can't prognosticate right now will be in that group."
Tampa Bay's Archer and Detroit's Michael Fulmer are the two names most often mentioned in potential trade conversations, but neither team appears to have any urgency to move them. Archer is owed $7.5 million next year and has a pair of club-friendly options for 2020 ($9 million) and 2021 ($11 million). Fulmer won't even reach the first of his four arbitration-eligible seasons until the end of this year, meaning the Tigers control him through 2022.

What's more, each comes with some red flags. Fulmer missed most of last season after undergoing elbow surgery, while Archer's ERA currently sits at 4.68, and was above 4.00 in each of the previous two seasons.
"The Rays have been very unrealistic in their expectations to this point," said the second NL executive. "If that doesn't change, they'll probably keep him."
Sonny Gray joined Verlander and Yu Darvish as the big-name starters moved last summer, going from the Athletics to the Yankees in one of the bigger pre-Deadline deals. The consensus within the industry is that the Yankees will try to add another starter this summer, though Brian Cashman's modus operandi in recent years has been to acquire younger, controllable players, which wouldn't fit the description of a pitcher such as Hamels.
"They talked about [Gerrit] Cole in the offseason, they talked about Fulmer in the offseason; that's what they're looking for, not a rental," the NL GM said. "Cash just got a new deal, he has a young team; I don't think there's any pressure on him whatsoever."
For teams seeking a high-impact rental, the most notable starters potentially headed for free agency are Clayton Kershaw, Dallas Keuchel, Patrick Corbin and Charlie Morton, none of whom figures to be traded by their respective teams.
Lance Lynn hasn't been able to replicate his years of National League success in the American League, so even if the Twins throw in the towel, it's hard to imagine that Lynn would be the difference-making arm a contender would turn to. Perhaps Ervin Santana, who has missed the entire season thus far following finger surgery, or Jake Odorizzi (one more year of control) could get moved, though neither adds much intimidation factor to a team's rotation.
"Trying to predict who the big starter will be at the deadline will be difficult," a second AL GM said. "It's going to be a lot of bullpen pieces. Teams are going to pluck off a lot of relievers."
The biggest wild card of the summer pitching market might wind up being Matt Harvey, who is working to regain his old form in Cincinnati after being designated for assignment and later traded by the Mets.

No matter how you slice it, the current landscape doesn't appear to include the potential for a race-altering starter to be moved. But that doesn't mean we won't see teams deal for arms with the hope of catching lightning in a bottle.
"The good money is that somebody will be available who has a chance to be at least a mid-rotation starter," the first AL GM said. "I think it will be more in the Sonny Gray, Jose Quintana types -- a nice pitcher that, if you really like him, he's a 2; if you're more realistic, he's a 3 -- than anybody who is going to do what Verlander did last year. The free agent class might offer that up. I'm not sure the Trade Deadline will."