With depth everywhere and an absence of soft spots, the 49ers may be unlike any other team in the NFL. Many league observers consider their roster to be the best in the sport. How the 49ers came to be so loaded was explained well on May 8, 9 and 10, as their roster was built with a philosophy that was reflected in a series of draft day moves.

First Round: S Jimmie Ward drafted with the 30th overall pick

The interesting aspect of this move is that there was a wide variance in how Ward was valued by NFL teams. Ward is small, played against mid-level competition at Northern Illinois and recently had foot surgery. Three front office men said they thought he should be a third-round pick; one general manager said he had Ward rated as the best safety in the draft.

The 49ers, though, don't care what the general manager or the other front-office men think. They care about what their scouts and coaches think. It's one of the traits that define their roster-building. "When we're evaluating players, we are evaluating their fit for us, period," general manager Trent Baalke explained. "We're not evaluating their fit for any other organization. We are evaluating how we perceive them to fit for us, schematically, within the locker room, within their individual position room, and in our community."

They perceived Ward as a fit on many levels, including in their system. The 49ers believe Ward eventually can be a starting safety, but he was drafted for a very specific reason -- to play the nickel corner position this year -- and for that, they believe he is ideal. "There is plenty of film that supports his ability to cover in the slot, which is what the nickel does," Baalke said. "The nickel has to have a lot of tools in his toolbox. He has to be able to cover slot receivers. He has to be able to play fast and physical in the run game. And he has to be very instinctive. He has to be a very smart player because there are a lot of things that happen that they have to be able to adjust quickly to and coordinate themselves with the back half in the coverage principles as well as the front half in the run fits. He was a young man that we felt had all of those qualities, and was a very passionate player, a high-energy guy. On film he erased a lot of mistakes that others made."

When Baalke was a young scout for the Jets in the late 1990s, Bill Parcells and Dick Haley taught him there are few players who can perform at a high level regardless of system. Picking 30th, you are not going to even sniff one of those players. So the challenge is to find players like Ward who match up with systems. "I learned that a long time ago," Baalke said. "Coach Parcells was the guy I looked at and learned the most from, he and Dick Haley. That was always the question with them, how do they fit what we are going to ask him to do? For us, it's critical."

Between first & second rounds: WR Stevie Johnson acquired from Bills via trade for conditional 2015 pick

This draft was rich in wide receivers, and the 49ers were flush with picks. But they weren't only considering receivers who were available in the draft. When Baalke found out he could get veteran Johnson for a future conditional pick that would either be a fourth- or third-rounder, he was very interested. With a fourth- or even third-round pick, chances were not good that he could draft a receiver who could impact the 49ers as much and as quickly as Johnson could.

Johnson is one of three wide receivers on the roster Baalke has traded for, along with Anquan Boldin and Jonathan Baldwin. The 49ers also found one of their receivers working for an aerospace company, as 32-year old Brandon Lloyd came out of retirement this offseason to join the team.

The depth chart at the receiver position shows how the 49ers consider all avenues to build their roster. Baalke learned to be open-minded by following the lead of Patriots coach Bill Belichick, with whom he worked when they were on the Jets. "The way he uses all elements of transactions to improve the team and create competition within the team has impacted what we do here," Baalke said. "Free agency, the draft, trades, every avenue possible the Patriots have done and they've done it very well. He's somebody I think a lot of people study."

Second round: RB Carlos Hyde drafted with the 57th overall pick

This was surprising to some, because the perception was the 49ers did not need a running back, let alone the highest-rated running back in the draft. They have Frank Gore, who remains one of the NFL's best, and last year they drafted Marcus Lattimore, at one point the most dynamic runner in college football. But they believed they could not ignore Hyde because of another tenet they adhere to: never pass up a player who fits and stands out on the board, regardless of need.  

Baalke said he puts together his draft board not by considering where a player is supposed to be picked, but by what the 49ers expect that player to do in the NFL. "Is that young man going to play like a starter or like a utility guy, a backup?" Baalke said. In the case of Hyde, the answer was he could play like a high-level starter.

"We felt Hyde was clearly the highest rated player on our board, and he's a young man that fits," Baalke said. "He fits our scheme and what we were looking for from a character standpoint. It was a high value, good fit. When those things come together like that, you jump at it."

Third round: C Marcus Martin drafted with the 70th overall pick

The 49ers are known as a physical team that wins the line of scrimmage. It is not by happenstance. Baalke likes to talk about how "big wins." That led them to Martin, who checked in to rookie minicamp over the weekend at 320 pounds. That makes him the largest center in the NFL along with Manny Ramirez of the Broncos, who also is listed at 320.

Twenty-seven picks before Martin was chosen, Weston Richburg became the first center selected. Richburg, who went to the Giants, weighs 22 pounds less than Martin. It's safe to assume that as far as the 49ers are concerned, they chose the best center for them. "He's a big man," Baalke said. "We look for big, physical and smart in our offensive linemen."

Some teams focused on Chris Borland's flaws, but the 49ers loved that all he did was make plays for Wisconsin. (Getty Images)

Third round: LB Chris Borland drafted with the 77th overall pick

Baalke was hired by then 49ers-general manager Scot McCloughan in 2005 as a regional scout. McCloughan left the team five years later after drafting many of the team's core players, but one of his legacies is how the 49ers front office still places so much emphasis on how players performed in games. "If I learned anything in all the time we spent together it's the value of the film, trust the tape," said Baalke, who still considers McCloughan a good friend. "Some of these guys can fool you. They can go to the combine and run faster than you expect, they can look a lot more athletic in the shuttles than they maybe are. But the eye in the sky doesn't lie. That's one thing I always appreciated about Scot. It was about the film and the makeup of the player."

Before the draft, Baalke talked about how Jerry Rice, the greatest receiver in history, ran a 4.59 40-yard dash. That number isn't remarkable, yet no one ever saw him caught from behind.

So along comes Borland. The Wisconsin linebacker is 5-foot-11 with 29 ¼ inch arms. He runs a 4.78 40-yard dash. His vertical jump is 31 inches. And a lot of teams are picking holes in him. "His arms aren't long enough, he doesn't run fast enough, he doesn't jump high enough," Baalke said. "Whatever the case is, you turn on the film and he's making plays. Is he an exception to our rule relative to the physical traits of the position? In some ways, yes. But at the inside linebacker position, the No. 1 criteria is 'do they make plays?'"

Borland also appealed to the 49ers because of his intangibles. Baalke worked with Joe Gibbs for a year in Washington, and he has not forgotten what the Hall of Fame coach emphasized in player evaluations. "He was looking for high character and intelligence, on the field and off, players who can make smart and quick decisions," he said. Gibbs, who used to like to say, "I'm just a P.E. coach," also was drawn to blue-collar guys, Baalke said. Which 49ers pick would Gibbs have liked most in this draft? Baalke thinks it's Borland.

Third round: The 49ers trade the 94th overall pick to Browns for a fourth-round pick and a sixth-round pick

In the last three years, the 49ers have made 17 trades involving draft picks and selected 30 players. He clearly sees value in the warehouse store shopping mentality, as depth has been built by bringing in players in bulk.

The team has parlayed its trade of quarterback Alex Smith to the Chiefs into defensive end Tank Carradine, Hyde, Borland and a 2015-fourth round pick. This year, the 49ers added a dozen players, and coach Jim Harbaugh said he believes each of them has a chance to make the team. Among the new picks are three cornerbacks, including fourth-rounder Dontae Johnson, and you can make that four if you count Ward as a corner. It is, Baalke said, a way to "infuse some youth and create some competition at the position."

When the 94th pick was approaching, the 49ers saw more value in what the Browns were offering than their board was promising. So they did the deal. "We feel regardless of how many picks you have, the No. 1 objective is to make your team better," Baalke said. "If that involves trading up to get players who can help us or standing pat or even backing up, that's what we do. When you back up, it's not always with the sole purpose of acquiring more picks. It can be that you don't feel there is somebody there at that point, or you feel by moving back you will get the same value and can add another player or couple players via draft choices. You let the board do the talking."

Third round: OT Brandon Thomas drafted with the 100th overall pick

One month before the draft in a private workout for the Saints, Thomas tore his ACL, which meant the 2014 season almost certainly would be a redshirt season for him. Many teams dropped him on their draft boards and lost interest. The 49ers, meanwhile, saw an opportunity to acquire a player who could help them in the future at a good value.

Baalke isn't looking at prospects solely for how they can help now. Mike Iupati has been an important player for the 49ers on the offensive line, but he is coming off a broken fibula and he's heading into a contract year. Thomas gives the team an insurance policy in the event Iupati leaves.

Thomas was one of three players the 49ers drafted this year who are coming off ACL injuries. Fifth-round cornerback Keith Reaser and seventh-round fullback Trey Millard both tore ACLs last season. In the 2013 draft the 49ers selected two other redshirt players coming off knee injuries, Lattimore and Carradine.

While ACL injuries can diminish explosiveness, cutting ability and longevity, most athletes can recover sufficiently. So the way Baalke sees is, patience is a worthwhile price to pay for exceptional value in the draft. "The long-term picture is just as important as the short-term," he said. "And sometimes you have to assume a little more risk for the upside of the reward."

One reason the 49ers like WR Bruce Ellington so much is because he's more than just a football player. (USA TODAY Sports)

Fourth round: WR Bruce Ellington drafted with the 106th overall pick

Ellington appealed to the 49ers in part because he also played basketball at South Carolina. In fact, he didn't even play football his freshman year. When Baalke was the defensive line and strength coach for Mike Daly at South Dakota State in the early 90s, he learned a lesson about multisport athletes. "From my experience there as a coach and recruiter, we had a lot more success when we took two- and three-sport athletes and developed them than when we took the high school football player who did nothing but play football 365 days a year," Baalke said. "We found we had more success with guys who played multiple sports."

Ellington is not the only member on the 49ers with a multisport background. Quarterback Colin Kaepernick had a 90 mph fastball and scholarship offers for baseball, and he also was an all-conference basketball player in high school. Tight end Vance McDonald was a basketball center, a long jumper and a triple jumper in high school. And British discus thrower and rugby player Lawrence Okoye joined the 49ers last year as a defensive end even though he never previously played football.

The point is the 49ers are looking for athletes, not just for players with the specific skill it takes to perform at their positions. Sometimes multisport athletes have potential that has been stunted by divided attention, and the more they stick with one sport, the better they get. "There is upside built into our assessment of Bruce because now he can concentrate on one thing, one sport, and really delve into the mental as well as the physical side," Baalke said.

Fifth round: DE Aaron Lynch drafted with the 150th overall pick

One of the reasons the 49ers chose Aldon Smith with the seventh overall selection in 2011 is that they were impressed with his wingspan of 83 7/8 inches and his arm length of 35 3/8 inches.One of the reasons they chose Lynch is they were impressed with his wingspan of 81 7/8 inches and his arm length of 34 inches. Lynch was an inconsistent performer with questionable intangibles, but he is the physical prototype for a 3-4 outside linebacker in the 49ers defense -- which made him a worthwhile gamble.

You can't coach that kind of reach, and it's something the 49ers look hard at in evaluations. "I can't say it's the only trait that matters, but long arms create better leverage," Baalke said. "Especially if they can use that length to their advantage. Some guys have long arms but don't play long-armed. Some guys have short arms but play long-armed. If they do take advantage of the length, it certainly is an asset."

What we witnessed from the 49ers was more than just the acquisition of Lynch and 12 other players. It was a lesson in NFL roster science.