With training camp set to open this week, the Falcons appear to have some apprehension about their offensive line.

Over the past two seasons, the unit was ravaged by injuries, and the Falcons are still counting on key players to rebound from major surgeries as the players report Thursday and hold their first practice Friday.

On Tuesday, the team worked out former four-time Pro Bowl tackle Jake Long. With the Falcons determined to run the ball in offensive coordinator Kyle Shanahan’s outside-zone-blocking scheme, Long would be the third veteran offensive linemen signed since mid-May.

The Falcons also drafted tackle Jake Rodgers in the seventh round and signed two guards — Jared Smith and Mike Person — in free agency.

The Falcons signed former Washington Redskins tackle Tyler Polumbus on May 14 and guard Chris Chester on May 30. If the team signs Long, those three offensive linemen will have a combined 340 NFL games and 230 starts.

The Falcons have not been linked to guard Evan Mathis, another former Pro Bowler who was released by the Philadelphia Eagles.

The Falcons are in a bind at tackle with Jake Matthews, who struggled his rookie season and is coming off a foot surgery. Also, Lamar Holmes, who started 15 of 16 games in 2013, suffered what appeared to be a broken foot, coach Dan Quinn said June 17.

Long, who is recovering from his second ACL tear, was cut by the Rams in a salary-cap move that saved them $8 million in March.

Long once was considered one of the best tackles in the NFL, but the injuries have slowed his once-promising career. He has finished each of the past four seasons on injured reserve.

Long left the Dolphins after five seasons to sign a four-year, $34 million deal with the Rams.

Whether the Falcons can get the offensive line together, they already know that quarterback Matt Ryan and wide receiver Julio Jones are a lethal passing combination. While some are quick to write-off former Pro Bowler Roddy White, he caught 80 passes last season.

With the passing offense as the known commodity, the running attack, which averaged 93.6 yards rushing per game and ranked 24th in the league, is the unproven commodity.

Most of the offseason focus was on second-year back Devonta Freeman and rookie speedster Tevin Coleman, a third-round pick from Indiana. But undrafted running back Terron Ward is a viable dark-horse candidate.

“Terron Ward, I’m interested in seeing,” former NFL team president and general manager Bill Polian said recently. “That will sort itself out. As long as they stay healthy, they are pretty good (at running back).”

Ward, who’s 5-foot-7, 201 pounds, rushed for 1,843 yards and 22 touchdowns over his career at Oregon State. He also caught 87 passes for 664 yards and three touchdowns.

“We ran outside-zone and inside-zone, similar to here,” Ward said. “So, it’s not that unfamiliar to me, but it’s different because this is the NFL. It’s at a different speed. I’m just trying to find my niche.”

After going undrafted, Ward also attracted interest from Tennessee and Oakland.

Falcons running backs coach Bobby Turner made an early impact on Ward.

“Intelligence is a big thing,” Ward said. “You have to know what you’re doing out there. If you don’t know what you’re doing, you can’t play fast.”

Ward wouldn’t be the first unheralded back to succeed in Shanahan’s offense.

Arian Foster, who’s had success is Houston, was undrafted. In 2012, Washington’s Alfred Morris was a sixth-round pick out of Florida Atlantic, and last season former Georgia and Alabama State running back Isaiah Crowell played well for the Cleveland Browns.

But first, the Falcons have to get the offensive line settled.