Like a human body, a soccer team won’t go far without a healthy spine. Like vertebrae, the central pieces of a starting lineup — goalkeeper, center back, along the midfield and at striker — are integral to achieve success.

After missing the playoffs in its first two seasons, Minnesota United has made upgrades across its spine. The hope is that the additions will produce a team that can win on the Kentucky bluegrass at new Allianz Field in St. Paul, and ultimately will be good enough to make the MLS Cup playoffs in October.

The new pieces — goalkeeper Vito Mannone, center back Ike Opara, defensive midfielder Ozzie Alonso and central midfielder Jan Gregus — are expected to be in the Loons’ starting XI when they kick off the 2019 season Saturday against the Vancouver Whitecaps at BC Place.

They join attacking midfielder Darwin Quintero and striker Angelo Rodriguez. The midstream additions during the 2018 season will be chiefly responsible for scoring. But defense is the first priority for a Loons team that set an MLS-record by allowing a combined 141 goals in their first two seasons.

“I think obviously the season will speak for itself and results will speak for themselves, but in the end the way that we prepared in this window was exceptional,” club president Chris Wright said.

After what Wright called “an incredible amount” of analysis, United pinpointed five key areas needing immediate improvement. Wright oversaw the roster build primarily orchestrated by sporting director Manny Lagos, player personnel director Amos Magee and head coach Adrian Heath.

“We feel like the spine all the way down the middle was strengthened,” Wright said, “and that was a major goal going into this window.”

The Loons’ fifth acquisition was at right back, where they’ve inserted Romain Metanire, who comes from France’s top-flight Ligue 1. The Loons feel he has the athleticism and skill to close down wide attackers, and the pace to put stress on other team’s defenses.

The question now, Wright said, is “can Adrian find a way to use the blend of players that we have most effectively and improve our results on the field?”

That’s not the only question. The first inquiry is how much gas do Opara and Alonso have left in the tank? While both have been among the best at their positions for premier MLS clubs, they are 30 and 33, respectively. How well will they continue to perform?

“When you look at Ike and Ozzie, there is a level of character and real backbone — strength in terms of experienced players in the MLS,” Wright said. “(They) have started games and seen games out and know how to win games in the MLS. We really felt like that was important.”

Alonso, a routine MLS all-star, has played 302 total games the past 10 years with the Seattle Sounders. Opara, who was MLS defender of the year in 2017, has played 91 the past three years after injures kept him to 66 total the previous six years.

MLSsoccer.com commentator Bobby Warshaw, who had a seven-year playing career in MLS and Europe, dismissed concerns about Opara, whose biggest setback was a ruptured Achilles in 2015 that brought on thoughts of retirement.

“If you look at (Opara’s) injuries, they are fluke injuries,” he said. “If it was a hamstring or a back, the muscular injuries, that would worry me.”

On Alonso, Warshaw is taking a wait-and-see approach.

“I think this is uniformly true in sports: We don’t know with the new sports medicine at what point players decline,” he said. “Five years ago, it would have been an issue, but now these guys (are) getting treatment, massages and a whole new sense of sports science. Is 33 what 30 used to be?”

The primary question surrounding Gregus, Mannone and Metanire is whether they can adjust to a new country and league. With five straight road games before the club opens Allianz Field on April 13, the Loons will need these guys to hit the ground running.

“That is one of the challenges,” Wright said. “The question is how quickly they can acclimate to the league and climatize themselves to the styles of play inside the MLS?”

To bring Gregus to Minnesota, United reportedly spent more than $1 million in a transfer fee to FC Copenhagen, a significant figure in MLS terms. During preseason, he has impressed with his passing ability, especially long balls, and will be the club’s primary set-piece taker. But time will tell with the 28-year-old expected to be in his prime.

Alonso and Gregus “will protect the back four a bit better than we are used to in the past,” Heath said. “Ozzie’s responsibility is when Jan goes (forward) to cover in and make it a little extra barrier in there. He does naturally because he’s always done it.”

The Loons brought in Mannone on a one-year loan from FC Reading in England’s second division. His acquisition was secured after United walked away from previous target, Agustin Rossi, when a domestic violence accusation resurfaced.

Warshaw hasn’t watched Mannone since the Italian’s time with Arsenal, a premier club in the English Premier League, but he wonders about MLS clubs using one of eight coveted international roster spots at that position.

“I personally think it’s really weird .. when you look at the math,” Warshaw said. “I don’t think (last year’s starter Bobby) Shuttleworth is an elite goalkeeper in the league, but I don’t think he’s costing you points.”

At the other end of the attack, the Loons are looking for more production from Rodriguez. The Colombian forward joined the club in July with another reported $1 million-plus transfer fee. Rodriguez had four goals and an assist in 11 games a year ago.

This preseason, he has been sidetracked by a nagging groin injury and likely won’t start in the opener against the Whitecaps. Ecuadorian Romario Ibarra, another midseason addition in 2018, is the probable replacement at striker.

“There’s only one way to put it and that is (Rodriguez) was bad last year,” Warshaw said. “But I’m pretty forgiving on these guys coming to a new league. … I’m always pretty understanding that you should not expect these guys to do well right away. I’m more worried that there weren’t really any flashes and no points where it was, ‘Oh, I see it.’ ”

It’s hard to determine the most critical juncture of a spine, but for the Loons, it’s difficult to look beyond Quintero. In 2018, the Loons’ most-expensive player at $1.65 million dazzled with 11 goals and 15 assists after coming from Club America, one of the historic clubs in Mexico’s Liga MX.

After an electric start, including a hat trick against Toronto FC on the Fourth of July, his production faded down the stretch — one goal in his last eight games, although he did distribute six assists in that run.

One of the primary explanations for the lull was a lack of service to him higher up the pitch, meaning he had to track back to get the ball and was then forced to go longer distance to reach the net. Gregus is expected to help shorten that gap.

“Can we actually get the ball to Darwin quicker?” Heath said. “Because the more we get him the ball in the little pockets of space with more time … the more time he has to make decisions. We know generally his decision making is good. It’s something that we’ve spoke about.”