COSTA MESA, Calif. -- With young quarterbacks Kirk Cousins, Jimmy Garoppolo and Blake Bortles signing lucrative new deals this offseason, Los Angeles Chargers quarterback Philip Rivers could be considered underpaid.

After signing a five-year, $137.5 million deal in February, Garoppolo will be the highest-paid quarterback in 2018, earning $42.6 million in total compensation, according to ESPN Stats & Information.

New Washington Redskins quarterback Alex Smith ($42 million), Drew Brees ($27 million), Cousins ($26 million) and Derek Carr ($22.5 million) round out the top five in total compensation for quarterbacks in 2018.

Cousins signed a fully guaranteed, three-year, $84 million deal with the Minnesota Vikings in free agency that could shift the paradigm of how players negotiate deals in the NFL.

However, Rivers is tied with Tom Brady and Cam Newton at No. 18 on the list. Rivers is set to earn a reasonable $15 million in 2018 and has two years left on a four-year, $83.25 million contract extension he signed in August 2015.

Rivers has said he still wants to be on the field when the Chargers open the new Inglewood stadium in 2020.

“I’m at a point in my career where I know that -- and I feel like I have some good years left -- but I know I’m not going to be able to duplicate that here [in Los Angeles], talking length of time and that just really ingrained in the community,” Rivers said at the end of last season. “But I still am all in.”

Chargers brass likely will have to address Rivers’ contract next year, and he could be in line to receive a similar contract to the one 39-year-old Brees negotiated in order to stay with the New Orleans Saints this season -- a two-year, $50 million deal that included $27 million in guaranteed money.

At 36 years old, Rivers is still playing at a high level. He earned his seventh trip to the Pro Bowl last season, finishing second in the league in passing with 4,515 passing yards. He threw 10 interceptions, his lowest total in a season since 2009.

Rivers threw for more than 4,000 yards for a ninth season and is the fourth player in NFL history to post nine or more 4,000-yard seasons. (Peyton Manning has 14; Drew Brees has 12; and Tom Brady has nine.)

With 50,348 career passing yards, Rivers ranks ninth in league history.

Chargers general manager Tom Telesco has started the clock on finding an eventual replacement but said Rivers has more years of productive play ahead.

“I haven’t really had a timeline on him, per se,” Telesco said. “At that position, because it is so important, you’re always looking for who that next guy will be, so you’re always prepared to do that if the situation arises.

“Philip is as well prepared as anybody, and he’s still playing at a high level. I don’t really have a timeline for him, but I know he played really well for us this year, and I expect him to come back and do the same thing next year.”

For Chargers coach Anthony Lynn, Rivers provides veteran leadership and playmaking ability.

“Philip is like a coach on the field,” Lynn said. “That’s what you want from your quarterback. He studies and he prepares no different than I did. When he’s on the field, I feel really comfortable that he’s going to get our guys in the right position.

“He’s going to deliver the mail to where it’s supposed to go. I thought, as far as recognizing run fronts in defenses, a lot of plays we called in the run game was because Philip changed the plays. That right there, you can’t teach that. That’s hard work. He has his little SUV that he put his mobile office in. That thing is unbelievable. All the video, all the technology you want with it. I’ve sat in the back seat with him. He’s working all the time.”