The Patriots were one of the busiest teams on Saturday, the final day of the 2015 NFL Draft, swinging trades and making eight selections to fill most of the few remaining empty spots on their 90-man roster.

"We'll take what we have and work with it, improve it, change it as we see necessary. Just don't think in any way that this is a final roster," head coach Bill Belichick cautioned reporters when the draft concluded. "Not even close to it."

Be that as it may, Saturday's draft activity got underway quickly for New England, which owned the second pick of Round 4 (101 overall), which the team used to select Trey Flowers, a defensive end from Arkansas (6-2, 265). Given his size and the various positions he's played, it's unclear how the Patriots plan to use him, but he says he's not concerned.

"[Experts] were calling me a 'tweener, linebacker, edge rusher, defensive end," Flowers said on a conference call, "and I'm just glad that I can show that versatility and just be open to any type of scheme whether it's 4-3, 3-4, whether it's standing up or hand in the dirt, I'm open to anything. I'm just glad I put that out on tape."

With the 12th pick in Round 4 (111 overall), the Patriots went with an interior offensive lineman, Florida State's Tre' Jackson (6-4, 330). This was a pick many observers predicted could happen because of New England's recent success with and interest in o-line prospects from Tallahassee. This marks the second consecutive season that New England has selected a Seminole o-lineman (center Bryan Stork wound up starting as a rookie in 2014).

"Tre' played next to Stork for most of Bryan's career down there at Florida State," Belichick observed. "They know each other well."

"It's a great feeling to be alongside one of my old players, one of my old guys that I know so well," Jackson told reporters on his introductory conference call. He also mentioned how excited he was to be part of the Patriots after taking an official pre-draft visit to Foxborough.

"It was a great experience, just being able to see the facilities, walking through the facilities, and talking with the coaches."

At the end of Round 4, with the 32nd pick (131 overall), New England again went interior offensive line, taking guard Shaquille Mason (6-2, 304) from Georgia Tech. Mason revealed that he's already on friendly terms with Jackson because his new teammate originally committed to play college ball for the Yellow Jackets.

[wysifield-embeddedaudio|eid="326401"|type="embeddedaudio"|view_mode="full"]

"We met in recruiting and we've always just been [friends] – throughout college, we've always known each other," said Mason.

That friendly demeanor doesn't necessarily translate on the field, however, where Mason prides himself on being one of the tougher players, despite being a tad undersized for his position.

"I always have a competitive edge. The salty and tough [labels] – that's pretty accurate because I mean, going into every situation on the football field, somebody has to win and somebody has to lose. That's my mindset each and every play, so I bring that to the table each and every play."

The Patriots were scheduled to select again at 147 overall, the 11th pick of the fifth round, but they traded that choice to Green Bay. In return, New England received the Packers' 166th overall choice in Round 5 and 247th overall in Round 7, giving the Patriots an additional draft pick top add to their total (their 11th of this draft).

With pick 166, the Patriots snagged Naval Academy long snapper Joe Cardona (6-2, 242), one of only a handful of players at his position ever to have been drafted. Belichick characterized it as "a need pick, based on our situation" at the long snapper position.

"It's a tremendous honor and really a dream come true. I know that sounds cheesy," Cardona conceded, "but I always grew up watching the Patriots because they've been so good forever. I'm really happy and really grateful that Coach Belichick is taking a chance on me and giving me an opportunity to come out and play."

It's unclear when Cardona might be able to suit up for the Patriots, however, given his commitments to the military.

"Hopefully soon," he continued. "I'm definitely prepared, or in the process of preparing to step on the field next year. Ultimately, like I said, the decision is out of my hands, so hopefully soon. I'm just excited that I'm a member of the New England Patriots right now and that I'm going to be graduating from the Naval Academy here in a couple of weeks."

"It's not the first time we've had service academy players. We'll work through the process… Whenever he plays, hopefully he'll be able to contribute," Belichick told reporters Saturday night.

In Round 6, at pick 178 overall, Mississippi State linebacker Matthew Wells (6-2, 222) heard his name called by New England, followed by another Arkansas player, tight end A.J. Derby (6-4, 255) a short time later (202nd overall). Wells' size makes him a candidate to move back into the secondary as a safety, which Belichick acknowledged is a possibility when he comes to Foxborough. Derby is another player who has limited experience at his current position, having started as a quarterback in college.

New England finally addressed one of its most pressing needs in the seventh round when it used the extra pick from Green Bay at 247 to select Darryl Roberts of Marshall (5-11, 187). The Patriots closed out their 2015 haul of draft picks with 253 overall, a compensatory selection, to choose Alabama linebacker Xzavier Dickson (6-3, 260).

Belichick said his team would begin signing about "half a dozen" undrafted rookies over the next couple of days to fill out the 90-man roster limit. A few such players have already been reported to have agreed to terms with New England, including Michigan's Devin Gardner, a QB-turned-wide receiver, Georgia center David Andrews, and UAB defensive back Jimmy Jean.

Members of the rookie class are expected in Foxborough later this coming week and next weekend to begin the process of getting oriented with the team's system and procedures. That is the biggest challenge they'll face in the near term, according to Belichick.

"For the last six months, each guy's been an independent contractor, been on their own system. Right now, that's all changed. They need to forget about all that and become New England Patriots. That's what we're going to start getting to work on. They're done with that. It's a huge adjustment for them.

"Welcome to the NFL… that'll start Thursday."