For any team looking for a summer rental, there are two clear properties that stand out above all other options.

Johnny Cueto and Jordan Zimmermann are aces being made available for trade because their teams have one year of control before they can hit the open market as free agents. The Cincinnati Reds and Washington Nationals, respectively, do not believe they can sign their pitchers for market value, so they are attempting to get more than a compensatory draft pick for them before they can bolt, although both teams have engaged the pitchers on extension talks this month.

The market for both aces seems to have been tentatively set by Jon Lester, who signed a six-year, $155 million deal with the Chicago Cubs earlier this month, and it might go higher depending on what Max Scherzer gets later this offseason. While Cueto and Zimmermann have expressed a desire to stay with the teams that drafted them, they will do so only “if the numbers are right,” as Cueto’s agent, Bryce Dixon, told MLB.com’s Mark Sheldon. Both players have informed their teams they will not negotiate extensions once the regular season starts. 

“If it’s a fair value, like I have said all along, I would gladly sign,” Zimmermann said about a contract extension with the Nationals, via Chase Hughes of NatsInsider.com. “But at the end of the day, it’s gotta be something that’s fair and if it’s not, then I’ll be moving on.”

Assuming the Detroit Tigers will opt to keep David Price and that Cueto and Zimmermann are more desirable in trade than the Nationals’ Doug Fister, the question becomes which No. 1 starter is worth the price and risk of the one-year rental.

The first and biggest concerns are the prices. And, man, are they high.

The Reds have some hope to contend in 2015 despite a loaded National League Central to wade through, and they have already traded pitchers Mat Latos and Alfredo Simon. That means they are likely to hang on to Cueto and try to get him to re-up in Cincinnati, although they have open ears. 

It also means that if the Reds do agree to trade their ace, they will have to get the kind of package in return that makes them the unanimous winner in the deal. Or, as Jon Heyman of CBSSports.com put it last month, the Reds would have to be “absolutely overwhelmed” to trade Cueto.

The price for Zimmermann is no cheaper. There are two key clues to support that. First, Nationals general manager Mike Rizzo told The Washington Post‘s James Wagner, “We’re planning on having all three of them [at spring training].” He was referring to soon-to-be free agents Zimmermann, right-hander Fister and shortstop Ian Desmond.

Second, Rizzo appears intent on getting back high-profile, major league-ready prospects in return for Zimmermann, as he has targeted the Boston Red Sox and Seattle Mariners as possible trade partners, Fox Sports’ Ken Rosenthal reported. Both organizations have deep pools of young and controllable talent.

Rosenthal’s report also claimed Rizzo offered Zimmermann and Desmond to Seattle for hot prospects Taijuan Walker and Brad Miller but was rebuffed for obvious reasons—cost of the veterans ($27.5 million) and Seattle didn’t want to lose cheap control of Walker and Miller for rentals.

Assuming a team is willing to dig deep enough into their farm system to acquire Cueto or Zimmerman, each ace’s monetary cost is another issue. Zimmermann will make $16.5 million in 2015, more than twice the $7.5 million he made last season. Cueto will earn $10 million next year, clearly making him the more attractive target, especially since both will essentially pitch as 29-year-olds next season—Cueto turns 29 in February, Zimmermann in May.

Durability is a bit of a concern, since Cueto missed significant time in 2011 and 2013. He was limited to 11 starts in 2013 because of a lat muscle injury, but in his full years of 2012 and 2014, he ended up leading the National League in starts, pitched more than 200 innings, and finished in the top four of Cy Young Award voting both years.

For comparison’s sake, Zimmermann has made 32 starts in each of the last three seasons, although he topped 200 innings only once.

There is also the fact that Cueto has done the majority of his work in the launching pad that is Great American Ball Park, a stadium that surrenders home runs at the fourth-highest rate in the majors. Washington’s Nationals Park gives them up at the second-lowest rate, making Cueto’s home run numbers a bit more attractive. However, the Reds had a much better defense than the Nationals in 2014, which makes Zimmermann’s line last season more impressive.

The fact is both players will likely cost a fortune to acquire and will more than likely explore free agency rather than re-signing with a new team. Those risks are built in. Considering that plus the 2015 cost of each, Cueto may be the less risky acquisition simply based on what it would take to land him. Plus he has been better for longer and was arguably better than Zimmerman in the 2014 vacuum.

It does not seem likely either ace will be traded before they report to spring training unless their respective clubs significantly lower their asking prices. But if it happens, either pitcher could turn into the most impactful trade acquisition of the offseason.

Anthony Witrado covers Major League Baseball for Bleacher Report. He spent the previous three seasons as the national baseball columnist at Sporting News, and four years before that as the Brewers beat writer for the Milwaukee Journal Sentinel. Follow Anthony on Twitter @awitrado and talk baseball here.

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