Matt Slocum/Associated Press

On Sunday, Charlie Blackmon launched a solo homer for the Colorado Rockies in a 6-4 loss to the Seattle Mariners. It was a nice moment for Blackmon, who signed a six-year, $108 million extension with the Rockies in April.

Unfortunately for Blackmon and Colorado, nice moments haven't come frequently enough in 2018—and that extension is looking like an albatross in the offing.

The deal made some sense at the time. Blackmon was a legitimate MVP candidate in 2017 and finished fifth in voting for the award. He led the National League with a .331 average, posted a 1.000 OPS, cracked 37 home runs and paced all of MLB with 387 total bases.

Blackmon was 31 years old when he inked the extension (he turned 32 July 1). But after his '17 output, it behooved Colorado to lock him up before he hit free agency.

This season, however, he's tumbled back to Earth.

David Zalubowski/Associated Press

Granted, Blackmon has hit 17 home runs. But his OPS has fallen nearly 180 points from last year's tally to .822. His hard-contact rate has dipped from 39 percent in 2017 to 34 percent. In June, he posted a .683 OPS and managed just seven extra-base hits in 115 at-bats.

Are the new contract and concurrent expectations messing with Blackmon's head? His skipper intimated the answer may be "yes."

"This guy's the National League batting champ, he started the All-Star game, hit 37 home runs, knocked in over 100 runs from the leadoff position—he's going to be pitched tough the next year, for sure," Rockies manager Bud Black said, per Kyle Newman of the Denver Post. "I think Charlie has, at times, come out of his game a little bit."

Perhaps more troubling, Blackmon's defensive performance has taken a dive. He posted minus-five defensive runs saved and a minus-0.9 ultimate zone rating for his play in center field in 2017, already not great. This year, those figures have fallen to minus-22 and minus-8.9, respectively.

Blackmon's future, in all likelihood, is as a corner outfielder. That makes his offensive decline all the more worrisome.

This year—even if he's not in the MVP conversation—Blackmon should help the Rockies win games as they try to hang with the San Francisco Giants, Los Angeles Dodgers and Arizona Diamondbacks in the deep, balanced NL West. He might even go on a tear and get closer to his 2017 production.

That's a big "might," though. And it doesn't take into account the remaining five years on his extension.

In 2022, Blackmon has a $21 million player option. That's his age-35 season. The following year, Blackmon can opt in for a minimum $10 million option.

In 2015, Alex Speier of the Boston Globe dug into the data on players around Blackmon's current age, and his findings weren't rosy:

"...after turning 30, players experience a clear and steady decline in the likelihood that they'll be productive offensive contributors, with 33-year-old players delivering 2.0 WAR with less than half the frequency of players 26-29. The picture gets progressively uglier from there."

Wilfredo Lee/Associated Press

If this were the deep-pocketed Dodgers or New York Yankees, we'd shrug and look away. The Rockies are middle-of-the-pack in terms of payroll, however. A contract like this could cripple them going forward. If they pay a player nine figures, they need him to perform accordingly.

Blackmon got a vote of confidence from teammate and otherworldly third baseman Nolan Arenado.

"He hasn't changed because of the contract," Arenado said, per Newman. "Here, he's the same guy working hard, trying to find a way every day. What he did last year was ridiculous—he was setting records like crazy, and I wouldn't put it past Charlie that he can do it again. But it's not an easy thing to accomplish."

Not easy now, and not easy as he climbs into his mid-30s, when many players' skills erode and slip away.

Blackmon and the Rockies are crossing their fingers for more nice moments. They should also brace themselves for a steep, costly decline ahead.

All statistics and contract information current entering Monday and courtesy of FanGraphs and Baseball Reference.