For five months, the backup catcher struggling to hit .190 watched the All-Star first baseman play. He celebrated the towering home runs, marveled at the Gold Glove defense and the way Anthony Rizzo's individual successes lifted the rest of the Chicago Cubs. But over the course of the season, David Ross also came to know the rare moments when he didn't think Rizzo was giving his all. And for some reason, the finale of a critical, mid-September series in PNC Park against the Pittsburgh Pirates, the team the Cubs were chasing for the right to host the National League wild-card game, was one of those moments.

Ross wasn't going to let it slide.

A 14-year major league veteran, Ross understands as well as anyone the challenges of getting up for every game - especially a Thursday matinee at the end of an eight-game road trip. But he also realized Rizzo's importance to the psyche of the clubhouse. If Rizzo felt he could take a day off and coast, others in the clubhouse might feel the same. Ross couldn't let it happen.

With the bases loaded and nobody out in the first inning, Rizzo rolled over a 1-1 pitch from Charlie Morton, a pitcher with a career 4.54 ERA, grounding into a double play. Morton is "a pitcher I would expect [Rizzo] to have a good day against," Ross said. Two innings later, Rizzo walked with one out and advanced to third on a double by Kris Bryant. But Ross thought he could have scored. The inning ended with Rizzo stranded on third. In the dugout later, Rizzo asked if Ross thought he could have scored. That's when the 38-year-old sounded off.

"You want my honest opinion?" Ross said. "I don't think you came ready to play today. I don't see the intensity in your game. I don't see the intensity in your at-bats. I don't think you're bringing it."

Rizzo didn't like what he was hearing. Ross had played in less than half the Cubs' games. He'd struck out twice as many times as he'd gotten a hit. Like most team sports, a baseball player's clubhouse clout is generally tied to his on-field performance. But Rizzo respectfully listened to Ross. He took it all in. And two innings later, facing Morton for a third time, Rizzo crushed a 1-0 pitch into the right field bleachers to give the Cubs a 5-4 lead in a game they eventually won 9-6. After his home run trot, Rizzo made a beeline to Ross, planted his head into the catcher's chest and started punching him in the gut.

"I started screaming at him," Rizzo said. "It's one of those things ... [Ross] doesn't demand respect -- he earns it. He lets you know in a nice way, and he'll get on you in a rough way if he needs to. I tell him all the time I just want to go out and prove to him I can bring it everyday."

What is it about Ross that made Rizzo listen? How exactly did a 38-year-old backup catcher who has hit .190 the past three seasons become the Cubs' clubhouse leader? Why is Ross the player manager Joe Maddon refers to as a "force multiplier," someone who "brings out courage and strength in other people" and is an irreplaceable piece of the 2015 Cubs?

"It's hard to put into words," Rizzo said. "It's something that the guys that sit behind computers and make up all these new stats can't make a stat for."

Ross and Jon Lester speak almost a shorthand language now. The ace helped convince Chicago's brass to sign Ross this offseason. Nam Y. Huh/AP

The Cubs are the seventh straight winning team for which Ross has played. Wednesday night's wild-card game against Pittsburgh will mark the fourth time in the past six years that he has appeared in the playoffs. That includes 2013, when he caught the final out of the World Series for the Boston Red Sox. It isn't just dumb luck. Beyond his talents as one of the game's premier defensive receivers (he has spent most of the past three years as Jon Lester's personal catcher), Ross is one of those veteran clubhouse personalities whose leadership, character and competitiveness bring teams together and propel them to success. He is "the best I've ever seen at it," Maddon said. Baseball's every move is dissected, analyzed and assigned a statistical quotient, yet Ross is a maddening conundrum. His influence is impossible to quantify yet equally difficult to ignore.

On a baby-faced team that has started five rookies (three of four infielders were born in the '90s), Ross is the bald, salt-and-pepper-bearded man teaching the young Cubs how to win. When the organization tries to snap a nine-game postseason losing streak against the Pirates on Wednesday, Ross will be the veteran the kids turn to in the most pressure-packed situations -- even if he isn't in the game.

"He's been there," Cubs rookie Kyle Schwarber said. "He's caught the last pitch of the World Series. He's won a ring. He's been a part of one-run games in the playoffs. He's special. He's something this team needs. And a lot of people on the outside don't know it."

Ross has built his baseball philosophy around one guiding principle: accountability. He has played for seven teams in 14 years, learned from clubhouse leaders and squashed clubhouse cancers. He knows how the game can beat you down, how failure is guaranteed more often than success. He tries to pass on those lessons in pursuit of winning.

"If I go out there and give a 50 percent effort, there should be somebody to call me out," Ross said. "Otherwise, you're going to be playing for nothing in September, and everybody is going to be miserable. I know stats can be selfish, and some guys don't believe in chemistry. That's fine. I'm sure teams have won without good chemistry -- but none of the teams I've been on."

Ross' camaraderie was on display again a few days before the end of the regular season, prior to a game against the Milwaukee Brewers. Lester was taking hacks in the cage as Ross looked on from third. After watching him crush a pitch into the empty bleachers in right, Ross noticed Lester alter his stance for the next batting practice pitch.

"No, no, no!" Ross bellowed from third. "You start hitting the ball hard, so now you change your stance and try to get more power? C'mon, now. No, no, no. That's something I would do. You know you don't want to hit like me."

Everyone chuckled. But the jab had a point: Don't give up an at-bat. Not even in batting practice.

Lester is as familiar with Ross' shtick as anyone. In May 2014, when they were both still with the Red Sox, Lester entered the eighth inning with 12 strikeouts in a start against Oakland. Then he walked Derrick Norris on four not-even-close pitches. Ross grabbed a new ball from the umpire, flipped off his mask and began barking his way to the mound.

"Are you done?" he chirped at Lester. "Are you quitting? Do we need to get somebody else out here?"

"He kept yelling at me and yelling at me -- and everyone in the park knew he was yelling at me," Lester said. "But that's what I needed. I pulled it together and went on to punch out the side for 15 strikeouts."

Cubs management had heard stories such as that when they signed Ross over the winter. They were rebuilding the organization with a blend of young talent and high character, knowing all too well the pressures likely to come with trying to win the World Series as a member of the Cubs. Lester, the team's prized $155 million acquisition, pleaded with the Chicago brass to sign his friend and former Boston teammate.

"You cannot overstate the chemistry thing and what he does to help your team win," Lester said.

After a two-hour lunch with Ross during last year's MLB playoffs, Rizzo came away equally impressed. "He was exactly what we needed for our clubhouse," he said.

Just before Christmas, the Cubs offered Ross a two-year, $5 million contract with an assurance that they valued his off-the-field intangibles as much as his on-the-field talent. "That meant that when I was hitting a buck eighty, they weren't going to say, 'Let's get this guy outta here,'" Ross said. "And that meant a lot."

The first time Ross walked into the Cubs clubhouse for spring training, he felt the way he always does with a new team -- like a "nervous wreck," he says. Brought in to build chemistry, he wondered if he would fit in. He worried how he would be welcomed by Wellington Castillo, who caught 110 games for the Cubs in 2014 but likely knew his days in Chicago were numbered after the team signed Ross and traded for Miguel Montero. But Castillo handled the potential awkwardness like a professional and, like Ross, focused on getting better and helping the team win.

So Ross did what he always does: He learned everyone's name as quickly as he could. He said hello to everyone each morning in the clubhouse. He refused to judge anyone on his reputation. And he used one of his greatest tools, poking fun at his own baseball failures, to endear himself to his teammates.

"I'm not a tough guy," he said. "I'm not a great player. I'm not too big to say, 'You're better than I am. I'm glad you're on my team so I don't have to face you anymore.'"

Cubs manager Joe Maddon believes in the intangibles of chemistry as much as Ross. AP Photo/Gregory Bull

As Rizzo said, the element players such as Ross bring to a team can't be analyzed in any concrete way -- at least not yet. Cubs Vice President of Player Development Jason McLeod admits the team has tried a number of psychology and personality tests over the years, but the front office still believes the best way to know a player is through human scouting. In a 2010 interview with The Seattle Times, the founder of sabermetrics, Bill James, drew an analogy between baseball and any work place: All of us work better if we like the people with whom we are working.

"Baseball would be quite a remarkable activity if it was the one place in the world where your coworkers didn't have any impact on how productive you were," James said.

Royals outfielder Jonny Gomes, who, like Ross, has a reputation as a clubhouse leader, agrees. Gomes came up with the Rays under Maddon and has played in four straight postseasons with the A's, Red Sox and now Royals, who open their divisional-round playoff series Thursday.

"Here's this game where we have statistics that are almost like geometry," Gomes said. "But there's not one stat on this. Nothing. No 40 percent this or X minus frickin' whatever. But you better believe that when you're on second and your buddy is up to the plate, you're going to be grinding to get in for him."

Ross forged his leadership abilities, as well as his abilities to make friends and adapt to new situations, as a young boy growing up in a rough, racially charged section of Tallahassee, Florida. In Tallahassee, Ross' quest to become a better baseball player led him to hang out with an older crowd.

"If I wanted to play, I had to step up and fit in," he said. The same held true in college at Auburn and Florida.

Once in the major leagues, Ross learned how he wanted to treat people. "When you're a rookie and a veteran is worried about you taking his job and is hazing you -- you remember how that feels," Ross said. "I don't want to make people feel that way. I want to win. You can't put guys down or make them feel like crap if we need them to win."

Over the course of the 2015 season, that positive, friendly, team-first approach helped Ross establish himself as the most respected veteran voice in the Cubs' clubhouse. In the games in which he didn't play -- there were 90 of those this year -- he high-fived teammates each time they came in and out of the dugout. He applauded great plays. He pointed out mistakes. He tried to help rookies such as Bryant, Schwarber, Addison Russell, Jorge Soler and Javier Baez cope with the ups and downs of a major league season.

"We can't have our third baseman down on himself because he hasn't had a hit in a week," Ross said. "I would tell them, '0-for-14? That's it? Let me tell you about my 0-for-21 with what felt like 37 strikeouts.'"

Anthony Rizzo says Ross' influence on the team is "hard to put into words." AP Photo/Ann Heisenfelt

Maddon loved how it all worked. The manager is a longtime proponent of character and chemistry, believing those are the attributes that push you on the days when talent alone isn't enough. In the eight-month grind of a major league season, when players spend far more time with their teammates than with their families, Maddon tries to keep things light by bringing magicians and animals into the clubhouse.

"When you are not on top of your game, you need this other thing that helps push you over these weak-minded moments when negativity starts creeping in, when the momentum starts going in the wrong direction," Maddon said.

That is precisely what Maddon had in mind in the final inning of a dreadful, three-game sweep by the Phillies in late July at Wrigley Field. Three straight losses at home to the worst team in baseball -- one of which resulted in the Cubs' being no-hit for the first time in 50 years -- saw the team's odds of playing in the postseason plummet from 70 to 43 percent. Trailing 11-4 in the ninth inning of the series finale, Maddon sent Ross out to pitch. Ross had thrown a 1-2-3 inning against the Mets in May, but he isn't particularly fond of pitching, fearful the opposition will smack one of his 70 mph meatballs right back at his face. Even so, Ross understood the importance of saving an inning for the bullpen. Without hesitation, he took the ball.

Ross threw eight pitches that inning, none of which exceeded 72 mph. It didn't matter. The Phillies only managed a harmless fly ball to left and a pair of grounders to short. Ross retired the side in another 1-2-3. Fans who had not yet left finally had something to cheer. And when Ross stepped to the plate to lead off the bottom of the ninth, they chanted his name. "Forever Young," his walk-up song, blasted on the stadium speakers.

On a 2-2 count, Ross took a hanging 88 mph slider and parked it in the left-field bleachers for his first home run as a Cub. Although the scoreboard read Phillies 11, Cubs 5, Wrigley erupted.

"You would have thought it was the go-ahead homer," Lester said. "The place went nuts. He went nuts. We all went nuts."

The Cubs lost by that same score, but in the aftermath, there was less talk about all that was wrong with the team and more talk about what Ross had done. Maddon compared him to Babe Ruth, and the rookies received the below-the-surface message: There is no need to panic. Everything is going to be fine.

Beginning the next night with a 9-8 walk-off victory over Colorado, the Cubs won 16 of their next 18 to climb from five games over .500 to 18 over. Ross's ninth-inning heroics and the levity they created are at least partly to thank.

"Absolutely, that turned everything around," Maddon said. "Because he's such a leader and so respected, it became a galvanizing moment for the group."

Sometimes, when he's not catching, Ross even takes a turn on the mound. Mike McGinnis/Getty Images

Four days after the Cubs' mid-September victory over the Pirates in which Rizzo responded to Ross' challenge by hitting the home run that gave Chicago the lead, some 40,920 fans were crammed into Wrigley Field, standing on their feet and roaring. The bases were loaded with nobody out in the eighth inning of a series finale against rival St. Louis. The Cubs were one base hit away from completing a rally that would give them a lead and likely a three-game sweep of the best team in baseball.

On the top step of the Cubs dugout, Ross took his customary spot atop a miniature stool. He had caught seven innings of six-hit, four-run ball before being lifted for a pinch hitter in the seventh. He had gone 0-for-2 on the day, which dropped his batting average to .189 and all but confirmed he would fail to hit above .200 for the second straight season.

The series, for both teams, had featured beanballs, managers getting ejected and purposeful, message-sending slides into second base. Maddon had even compared Cardinals manager Mike Matheny to television mobster Tony Soprano. It was exactly what you might expect from an end-of-the-season Cubs-Cardinals series that, for the first time in years, actually mattered. And it was the exact type of playoff-like atmosphere Chicago's young players needed to experience.

As Chicago threatened to take the lead, Ross looked around the dugout at his teammates. He sensed their tension. At the opposite end of the dugout, he noticed second-year reserve outfielder Matt Szczur sitting quietly.

"Soak it up, Matty!" Ross yelled. "This is why we play the game."

Although the words were directed at Szczur, they were intended for everyone. The message: Step outside the moment ever so briefly, and be a fan. Take it in. These 40,000 people are screaming for you. This is why we've worked so hard.

Ross understands this because he has been there -- in the World Series and in a win-or-go-home wild-card game like the one the Cubs will play Wednesday. In 2012 with Atlanta, Ross was a surprise starter in place of Brian McCann against the Cardinals, and he went 3-for-4 with a home run and two RBIs in a 6-3 wild-card loss. He says he went to the bathroom seven times before the game began. A year later, he watched from the on-deck circle as Stephen Drew homered in Game 5 of the 2013 World Series, and Ross turned to the crowd to absorb its electricity. He has learned to enjoy those moments and embrace the anxiety.

Now, with a sweep of St. Louis at stake, Ross wanted his Cubs teammates to do the same. Szczur chuckled at Ross' suggestion. So did a bunch of other Cubs. The tension broke.

On that day, however, there was no magical, come-from-behind Cubs win. Russell, the rookie shortstop, lifted a fly ball to right, and Jason Heyward snagged it before throwing Rizzo out at home to preserve a 4-3 Cardinals win. But the lesson wasn't lost.

"We got better that day," Ross said. "We went through a lot of turmoil but almost won that game. That's only going to help us."

Ross celebrating with Hector Rondon after a big Cubs win over the Pirates in September. Justin K. Aller/Getty Images

Although he has struggled at the plate, Ross has caught seven shutouts this year. He has been behind the plate in seven other games in which the Cubs allowed just one run. The team is 22-8 in his past 30 starts. But he knows his days as a major leaguer are numbered. While the 2015 postseason might be the first crack at a World Series for the baby Cubs, 38-year-old Ross has been around long enough to understand it could be his last. He could be 21-year-old shortstop Addison Russell's father.

"The guys these days want to play video games," Ross said. "Well, my kids play video games."

Whenever his last game arrives, be it Wednesday, later this month or next year, a future as a broadcaster or perhaps a major league manager awaits. Maddon thinks Ross would be "perfect" to lead a ball club in a more official capacity. "Any team would be lucky to have him," the manager said.

On Wednesday against the Pirates, Ross says he won't do anything differently than what he has done all year. He knows if he or Maddon or anyone else starts showing panic, the paranoia will spread. If something should go wrong in the game, Ross will take it upon himself to focus on the positives and remind those on the field to keep fighting, to not give up a single pitch in a single at-bat.

"Just bring that sense of calm," Ross said.

It's what he has tried to do from the beginning.

"Chris [Denorfia] said to me the other day, 'Do you think the young guys like us, or are we the veterans that we hated when we came up, the assholes that you were always like, "Why is this guy always on my ass?"'" Ross said. "I told him I don't know.

"I joke with the guys all the time. My role on the team? I'm the best high-fiver there is. I give great high-fives. That's my role. I give the best high-fives."