Mel Kiper Jr. sees Kyler Murray, Dwayne Haskins, Drew Lock and Daniel Jones all being selected in the first round of the NFL draft. (1:40)

NASHVILLE, Tenn. -- There's a saying in the NFL that a reliable tight end is a quarterback's best friend. Given how Titans TE Delanie Walker has been targeted over 100 times in each of his three full seasons paired with QB Marcus Mariota, that rings true in Tennessee.

The 13-year veteran has been the focal point of the passing game since arriving as a free agent in 2013. Mariota appreciates the impact Walker has on opposing defenses.

"Delanie was such a vital part of the offense, and he caused matchup problems. Teams tried to figure out how to match up against him or maybe even put two guys on him," Mariota said after Walker suffered a season-ending ankle injury last September.

Indianapolis Colts head coach Frank Reich echoed Mariota when asked why quarterbacks tend to favor tight ends.

"Well, you work the inside of the field. Shorter throws, balls in the air, less time, you’re working against linebackers who aren’t as good in coverage, possibly safeties. You have many of these tight ends who are almost like receivers."

At 34 and coming off a season-ending ankle injury, Delanie Walker could struggle to return to form. Winslow Townson/USA TODAY Sports

A former college wideout, Walker presents those matchup problems. Opposing defenses struggle to stop Walker because he is too fast for most linebackers to cover, and at 6-foot-2 and 248 pounds, he can outmuscle defensive backs. Last year, the Titans' tight ends combined for 63 receptions for 750 yards and seven touchdowns without Walker. By comparison, Walker himself averaged 71.2 receptions along with 831.2 yards and five touchdowns from 2013 to 2017.

Walker dominates the middle of the field on crossing routes, catching short passes and getting yards after the catch (his 1,438 YAC ranks fifth for tight ends between 2013 and '17). He also consistently beats defenders on seam routes for significant gains. It is imperative that new offensive coordinator Arthur Smith focuses on Walker's strengths and uses them to open up other options in the passing game.

Employing dual crossing routes with Walker and another pass-catcher will set up natural picks and cause defenders to get lost in coverage, creating an easy throw to the second option because Walker will draw most of the defense's attention. Smith can also use Walker on seam routes to create open windows for a deep in-breaking route by a secondary receiver underneath. There is an abundance of ways to benefit from the threat that Walker brings.

When the season starts, Walker will be 35. Before leaving the facility for the offseason, he said his recovery is going as scheduled. His goal is to be able to run and catch footballs in OTAs. He knows the questions about returning to form will arise and he welcomes the challenge.

"I don’t really remember how old I am," Walker said. "They can judge me all they want. I already know people are going to say it’s going to be a struggle to come back off an injury like this. They doubted me before and look how far I got. I am just going to prove everybody wrong."