The chances of the Chicago Cubs signing superstar right fielder Kyle Tucker to an extension have never been great.There has been optimism from the fan base as well as the front office, but it was always unlikely that a deal would be reached.That was further proven Thursday when MLB insider Jon Heyman revealed the true likelihood of a deal between Tucker and the Cubs."It's pretty unlikely that they're able to sign him," Heyman said via 670 The Score. "I'm not gonna say it's zero or 10 percent or that low, but I would say, let's be realistic, it's gotta be less than 50% at this point."Chicago's willingness to ever pay more than $185 million to a player has always been a factor when wondering if it would ever fork the money to keep Tucker. Jason Heyward's $184 million contract is the largest in the history of the franchise and it would appear to be unlikely that the front office doubles that to keep Tucker.The comments from Heyman come in the same week that Tucker was benched by manager Craig Counsell due to a career-worst slump. Tucker has seen his average drop from .280 to .261 since the All-Star break and he does not have a home run since July 19.There is a chance, though, that Tucker's recent slump could lead to a shorter contract with opt outs, similar to the one third baseman Alex Bregman signed with the Boston Red Sox.With a little over a month left in the regular season and with the postseason looming, Tucker still has more than enough time to get back on track. If he returns to the superstar caliber player he's shown in the past, he may put himself completely out Chicago's willing price range in the offseason.More MLB: Craig Counsell's Response to Kyle Tucker Injury Revelation Bad Look for Cubs