OWINGS MILLS, Md. -- The frustrations of the Baltimore Ravens' deep passing game can be summed up by latest disconnect last Sunday, when Joe Flacco's throw sailed low and wide receiver Mike Wallace dropped what would've been at least a 30-yard completion.

It's one of the more bizarre developments in a season filled with struggles for the Baltimore offense. Flacco has one of the strongest arms in the NFL. The Ravens have fast receivers in Wallace, Jeremy Maclin and Breshad Perriman. But it feels like Baltimore needs a (Mile High) miracle these days to get the ball deep downfield.

After four games, Flacco has completed only two passes on throws of 15 yards or longer and has been intercepted four times on such passes. That means twice as many of Flacco's deep throws have gone to the other team than the Ravens themselves.

"I think when some of those big plays are presented to us -- they're there, they've been pretty easy; you can make them in your sleep -- and we haven't made them," Flacco said.

The Ravens' inability to stretch the field is reaching embarrassing proportions. Flacco's average of 5.09 yards per attempt is the worst in the NFL since Bruce Gradkowski's 5.06 in 2006.

The other quarterbacks with worst yards per attempt averages under 5.25 since 2001 include: Kyle Orton, Joey Harrington, JaMarcus Russell and Brady Quinn. This shows the level of struggle for Flacco and the Ravens offense. There are bad quarterbacks, and then there are Harrington and Russell.

"Most definitely, it is frustrating," Wallace said. "When you have a guy who has one of the strongest arms in the NFL, and we have one of the fastest receiving corps in the NFL, you would think we would have big plays. But a lot more goes into it than just that."

One factor that goes beyond Flacco and his receivers is the Ravens' makeshift offensive line. Baltimore lost two starters (guards Marshal Yanda and Alex Lewis) and two backups (John Urschel and Nico Siragusa) for the season. Other than first-round pick Ronnie Stanley, the Ravens are starting three undrafted players and a former sixth-rounder in center Ryan Jensen.

As a result, Flacco hasn't had the protection to give him the time to throw deep. This could explain why Flacco has only attempted 15 passes of at least 15 yards downfield, which ranks 30th in the NFL. Seven quarterbacks have doubled that number this season, and Tom Brady has thrown a league-high 44.

"That is something we need to get to," coach John Harbaugh said. "It is important to us. We have speed. We need those guys making big plays for us, and we have not had enough big plays. When we have big plays, everything looks a lot better. We have to open that up a little bit and find a way to throw it over the top of people."

Flacco and the Ravens have to be shaking their heads on how it's gotten to this point. From 2009 to 2014, he completed 271 passes of at least 15 yards, which were the ninth-most in the NFL over that time.

In four playoff games in 2012, Flacco completed 19 of 40 passes (47.5 percent) that traveled at least 15 yards in the air, throwing five touchdowns and no interceptions. In four games this season, he has connected on just 2 of 15 (league-worst 13.3 percent) such throws.

"At some point, you have to start trying to make plays and push the ball up the field and do certain things that are going to turn the game around and back in your favor," Flacco said.

This has become a point of emphasis to stop Baltimore's two-game losing streak and jump start a plodding offense. Flacco and his receivers worked on the deep passing game after Wednesday's practice, and they hit on some.

On Sunday, Baltimore is playing an Oakland Raiders defense that hasn't allowed too many passes to go over the top. The Raiders have given up 10 completions on passes of 15 yards or longer. Only 10 teams have allowed fewer.

"We have to get it going no matter what the problem is," Wallace said. "Nobody cares about our problems. We just have to find a way."