Rockies third baseman Nolan Arenado’s poor offensive season actually started with a great defensive play in the season’s fifth game, during what was an outstanding season with the glove.

The constant pain since, and the team’s collapse -- from an 11-3 start to needing a near-miracle to make the playoffs -- led to Monday’s decision to shut him down for the final eight games. A diving stop of a Stephen Piscotty grounder in the second inning of a 5-1 win on July 29 jarred his left shoulder, although the severity didn’t immediately register with him.

“I thought it was from sleeping, but it just wouldn’t go away,” he said.

Arenado played in pain until Sunday, when tests revealed inflammation in the AC joint and a bone bruise.

“It was a mutual agreement,” Arenado said. “After we got the MRI yesterday I thought it was best I would start the rehab process right away, especially with where the team is. It’s kind of unraveled just a little bit. So I thought maybe the best to start it [rehab] now, get it going so I don't have to deal with this in the offseason -- being injured.

“If we were in it, I would like to believe that I would try to find a way. I think the trainers, they're good, and they know how to find a way to make it feel alright. But it's just probably the best thing to do, rest right now.”

Compromised offensively, Arenado, one of the game’s top hitters, batted just .253 with eight home runs and 26 RBIs in 48 games. His last two homers were Aug. 20 and Sept. 8, and his last extra-base hit was Sept. 9.

The only other time Arenado has been placed on the injured list in his career was May 24-July 3, 2014, with a fractured left middle finger.

Rockies manager Bud Black nonetheless entered Monday’s opener of four games at San Francisco expecting to make a push, with Trevor Story (12-game hit streak) moving to Arenado’s cleanup spot and Ryan McMahon moving from second base to third. Black used that strategy in Sunday’s 6-3 home win over the Dodgers.

“It became very nagging,” Black said of Arenado. “So the doctors felt and our trainers felt it was the wise thing to do, was to shut Nolan down, let it heal. Probably he’ll feel much better in about a month.

“At times it can be a rallying cry that guys know they have to step up when a player of Nolan's caliber is not in the lineup. So the guys will go out there tonight and fight.”

The Rockies recalled outfielder Sam Hilliard from the alternate training site and started him in right field, while listing regular right fielder Charlie Blackmon as designated hitter.

If the Rockies don’t make the unlikely climb to the playoffs, it will be two straight disappointing seasons, after postseason trips in 2017 and 2018. Before last season, Arenado signed an eight-year, $260 million deal, but the team went 71-91.

During the Winter Meetings, general manager Jeff Bridich said the team was willing to listen to trade offers, and in January Arenado went public with his displeasure with the front office.

With the Rockies entering Monday tied for the Majors’ worst record since their strong first 14 games, Arenado said he is wondering if changes are coming.

“All those things kind of go through your head,” said Arenado, who is due $35 million next season and has a full no-trade clause and a player opt-out available after next season. “I don't know what's going to happen next year, but I assume there's going to be some changes.”

Nevertheless, it was a standout year with the glove.

According to FanGraphs, his 15 Defensive Runs Saved lead all players at all positions (Braves shortstop Dansby Swanson is the only other player in the Majors in double figures with 10). Arenado has said that if the season had been longer, he might have been able to sit a few days, and he might have had time to return to his normal swing.

“I felt like my defense was better than it's ever been,” he said. “Offensively, I would have been there also. But I just wasn't, in the 60-game race."