Patriots backup quarterback Matt Cassel, eluding Buccaneers’ defenders on Friday night, could be under a sharper microscope from New England coaches as he enters his third season.

AP / Scott Audette Scott Audette

First-round draft pick Brandon Meriweather didn’t have to wait long to see his first action in the NFL — during Friday night’s preseason opener in Tampa, the Florida native came onto the field during the Buccaneers’ first drive, when New England trotted out its third-down dime package.

Judging by training camp repetitions, it appears that Meriweather will be a top reserve this season, but as a rookie still learning a new system, he was on the field for most of the game Friday night. He came away with three solo tackles and a starting point.

“I think that Brandon would fall right into the category with everybody else who played,” Bill Belichick said in his day-after conference call yesterday. “There were some things that he did that were good and there were other things that he did that could’ve been better that he’ll need to learn from and try to improve on the next time out.”

After missing the first day of training camp while the final details of his contract were being hammered out, Meriweather has shown improvement. He certainly has a nose for the ball, and got his first interception of camp last week — perhaps not coincidentally, during the special event for season ticket holders that drew more than 16,000 fans to Gillette Stadium.

The self-professed defensive back, who has lined up as a slot corner and at safety in practice, has said several times that his role is whatever Belichick asks of him.

Under the microscope

Backup quarterback Matt Cassel, who led New England to its lone touchdown of the night, always seems to be a big topic during the preseason — mostly because that’s the only time the former USC product is seen for any length of time.

As he begins his third season in the NFL, typically a time when coaches know if they have a star or a bust, Cassel seems to be under a sharper microscope this season than years past. Whether it’s because of Tom Brady’s age — he turned 30 last month — or the general fear that a freak injury like the one that eventually ended Drew Bledsoe’s career in New England could happen to Brady, there’s lot of talk about whether Cassel could lead the Patriots for any stretch of time.

Friday night, he flashed his foot-speed and some elusiveness, scrambling 12 yards on a third-and-13 during the Pats’ scoring drive. On the next play, he dove for the first down. Cassel also got the ball away quickly in the face of the Buccaneers’ rush, hitting Jabar Gaffney over the middle.

After the game, Cassel said he’s getting more and more comfortable in New England’s system: “You evolve after being in the system for three years and hopefully that continues.”

Miller stays grounded

Of the five punts New England had against Tampa Bay, none were taken by Josh Miller. Instead, Danny Baugher took three and Tom Malone handled the other two. Baugher averaged 44.3 yards per try, with a long of 48 yards; both of Malone’s punts ended in a touchback, though he averaged 46.5 yards.

While it continues to look more and more like Miller might not be long for Foxboro, Belichick said after the game he simply wanted to see what he’d get out of the youngsters; Miller is already a known commodity.

Beckham takes spotlight

The Patriots return to the practice field today for a 2:30 p.m. session, which is closed to the public due to the Revolution game — aka The Arrival of Beckham — tonight. …The team has a morning practice, also closed to the public, tomorrow, but Tuesday’s 2:30 p.m. session will be open to the public.

smanza@projo.com