The Jaguars finished 2017 with the NFL's best rushing offense (141.4 yards per game) and quarterback Blake Bortles was sacked a career-low 24 times.

So, why does it seem like upgrading the offensive line has been the top priority since then?

Those successes were diminished when the Jaguars slowed in the second half of the season and couldn't run effectively enough to take advantage of a 10-point fourth-quarter lead against New England in the AFC title game. That loss was a factor in the signing of All-Pro left guard Andrew Norwell and raises the question of whether they are done upgrading a unit that could be bolstered with an early round pick in next week's NFL Draft.

"We know how we want to play, how we want to control the game," Jaguars football boss Tom Coughlin said at the NFL meetings last month. "We'll take our shots down the field and do those types of things, but if we can maintain the ball [and] keep the other guy's offense off the field, it helps us."

Norwell, left tackle Cam Robinson and center Brandon Linder are important pieces in that philosophy. There is less certainty on the right side, where guard A.J. Cann and tackle Jermey Parnell are currently slotted in as starters.

The Jaguars like Cann's toughness. He led the offensive line with 1,231 snaps played last season but was responsible for a team-leading 21 "bad" run plays — carries that gained 2 yards or fewer in non-goal line or short-yardage situations — per the Times-Union's charting. Cann, a third-round pick by the Jaguars in 2015, has played 45 games (44 starts) in three seasons and is entering the final year of his rookie deal.

Prior to the AFC title game, Jaguars coach Doug Marrone praised Cann's work ethic but admitted he would have liked his on-field performance to be steadier.

"He's had some ups and downs with some consistency," Marrone said. "I'm sure he would have liked to play [better], but we are happy with him. He's one of those guys you can rely on. He's always out there, plays every game and [is available] at every practice. He keeps trying to get better."

Parnell missed three games with a knee injury last season but has played and started 44 of a possible 48 games since signing with the Jaguars prior to the 2015 season. He was booked for 13 1/2 "bad" run plays — fewest among the five starters — last season and is fine in pass protection. But at age 31 and with two years left on his contract, it's reasonable to wonder how long Parnell can continue to play at that level.

The Jaguars' opinion could depend on how Day 1 unfolds April 26.

One player who could interest them is Notre Dame left tackle Mike McGlinchey, who is a sturdy 6-foot-8 and 312 pounds and made 39 starts (25 at left tackle, 14 at right tackle) in college.

It's unclear when McGlinchey will come off the board, but he will almost certainly be a first-round choice. ESPN's Mel Kiper Jr. had McGlinchey going 21st to Cincinnati in a recent mock draft;'s Bucky Brooks had Philadelphia taking him at No. 32.

The Jaguars hold the No. 29 choice and could draft McGlinchey to start immediately and begin to shop Parnell or use McGlinchey as a swing tackle initially before he assumes the starting role in 2019. Josh Wells is currently the backup tackle, and Tyler Shatley is the team's top reserve inside.

If continuing to fortify the interior of the offensive line is seen as a more pressing need internally, the Jaguars will have several choices late in the first round. Notre Dame's Quenton Nelson is a likely top-10 pick, but Georgia's Isaiah Wynn, UTEP's Will Hernandez and Texas' Connor Williams — who could play guard or tackle — are also intriguing options.

Beyond the first round, tackles Geron Christian (Louisville) and Martinas Rankin (Mississippi State) are developmental players. At guard, Alex Cappa (Humboldt State) and Tony Adams (N.C. State) are just a couple of other possible choices.

The Jaguars haven't used first-round picks to improve the offensive line often. The last time they did was to get left tackle Luke Joeckel in 2013, and they have drafted just five offensive linemen in the last five years.

Given their commitment to building an offense around running back Leonard Fournette, it wouldn't be surprising to see a change in that trend. Even without a top-five choice, several quality options should remain available.

"You have to do a better job of [understanding] who’s going to be there and who’s gone and so on and so forth," Coughlin said of choosing 29th. "Over the years, some good things have happened in that spot."

Phillip Heilman: (904) 359-4063