PHOENIX -- Every season is different, but when one analyzes the struggles of the defending World Series champion Cubs in 2017, venture no further than two significant roster changes: the retirement of veteran catcher David Ross, and to a lesser extent, center fielder Dexter Fowler moving to the Cardinals as a free agent.
Both players had a huge impact, especially in the World Series. Both players homered in last year's epic Game 7 victory over the Indians that won the Cubs their first World Series since 1908.
"They're both missed sorely, badly, but I don't think that's the entire reason we're floundering right now," Cubs manager Joe Maddon said on Friday night before the Cubs opened a three-game series against the D-backs at Chase Field.
Fowler set the table as the club's leadoff hitter, opening Game 7 with a homer off Indians ace Corey Kluber at Progressive Field.
"I used to tell him, 'You go, we go,' and it was true, man," Maddon said. "When Dexter was hot, we were really, really hot."
"Grandpa Rossy," though, was the heart and soul of the Cubs both on the field and in the clubhouse. He was Jonathan Lester's personal catcher going back to their days in Boston when D-backs manager Terry Lovullo was the bench coach under manager John Farrell.
"We miss David for his edginess," Maddon said. "Beyond catching Jon, which he did a great job with, he supplied a voice, especially among the younger players. He held them accountable in the clubhouse and on the field, too."

Long before Ross became a folk hero in Chicago, he was the Red Sox's backup catcher behind Jarrod Saltalamacchia in 2013 for a team that defeated the Cardinals in six games to win the World Series. It was Ross' second tenure with the Red Sox after a one-month stay at the end of the 2008 season.
Ross was limited to 36 regular-season games during the 2013 season due to a pair of concussions. He had another in Chicago during the 2015 season, and that recurring injury eventually caused him to retire at 39 after the last World Series.
"There were times when what I was going through was overwhelming," Ross said during the 2013 Fall Classic. "My wife and the doctors said, 'You can't think about that. It's just taxing your brain.' The best thing they did was give me a plan of attack, almost a rehab program for my brain. I saw progress, and that's when I realized, 'I can come out of this.'"

Ross returned and was paired with Lester, making a major contribution to the Red Sox in that World Series. He was hardly a household name at the time, just a journeyman player with the sixth of his seven teams during 15 seasons.
His seventh-inning double in Game 5 at Busch Stadium drove in the winning run. But he turned into a favorite go-to-catcher, not only for Lester, but for fellow starters John Lackey and Jacob Peavy.
Ross started and caught Lackey in the Game 6 clincher at Fenway Park.

"David Ross was the backup catcher, but from the last week of the season on, he started to play every day," Lovullo said Friday. "He was deserving of that. He brought a sense of calmness to the pitchers. He worked game plans. He read swings. And he had some big at-bats, as well.
"It was very similar to what he did last year with the Cubs. Chicago embraced him at a different level. He's a very popular player, publicly and privately. In Boston, he was loved there, too."
Lester became a better pitcher with Ross as his catcher. Because of Ross, the left-hander reached a comfort level toward the end of 2013, finishing with a 15-8 record and 3.75 ERA season. Most importantly, Lester was 4-1 that postseason, with two of those wins coming against the Cardinals in the World Series, during which he allowed one run on nine hits over a combined 15 innings.
"Lester had a great game plan, and at that point of the season, [he] probably needed somebody to help him get to the next level and understand the stuff he had," Lovullo said. "David Ross was fearless in that department. He guides things in a good direction. That's what Lester needed at that time of his career, and you can see what he's turned into now."
Lester and Ross both signed with the Cubs as free agents before the 2015 season, and the marriage continued to the very last game of the '17 World Series when Maddon brought Lester in to replace Kyle Hendricks in the fifth inning and Ross at the same time.

It was the last time the two teammates worked with each other, causing a major alteration in the way the Cubs do things this season. Last year, Lester was 19-6 with a 2.44 ERA with Ross catching all 32 of his starts. This year without Ross, Lester is 9-6 with a 3.94 ERA through his first 24 starts.
No two seasons are alike, but this is a major difference.
"It's hard to replace guys like Rossy," Maddon said. "I'm not talking physical ability as much as I'm talking about presence, the people, the heartbeat. Those are the things that they supply for us that are impossible to measure, that are really important to success."