INDIANAPOLIS – Already young and short on depth, the Giants might be losing a rare veteran contributor.

Tight end Rhett Ellison is mulling retirement, according to three NFL sources, after missing the final six games of his eighth NFL season due to a concussion.

Ellison, 31, signed a four-year, $18 million free-agent contract in 2017 but was supplanted as the starter only six weeks later when the Giants drafted Evan Engram. The sure-handed blocking-first Ellison has 67 catches for 674 yards and four touchdowns in 40 games with the Giants, after spending five seasons with the Vikings.

Ellison’s contract calls for a $7.18 million cap hit this season – not in line with his role – but $5 million in savings and only $2.18 million dead money if he is released or retires. The Giants cut linebackers Alec Ogletree and Kareem Martin to save more than $13 million against the cap.

If Ellison decides he wants to stay with the Giants, his contract could be reworked for a pay cut.

It looked like Ellison was going to return in Week 16, but he suffered a setback and went from taking every practice rep one day to limited participant the rest of the season.

Tight end suddenly is a muddled position for the Giants as they scout the NFL Combine.

Engram remains in a walking boot after his late December foot surgery. He is one of the NFL’s best receiving tight ends when healthy but has missed 14 games due to injury in his three-year career.

The Giants must decide by May whether to pick up Engram’s fifth-year contract option for 2021. He is expected to be sidelined until training camp.

Scott Simonson is a free agent, leaving Kaden Smith and Garrett Dickerson as backups under contract. Smith is coming off 31 catches for 268 yards and three touchdowns as a rookie.

Giants offensive tackle George Asafo-Adjei, who missed his entire rookie season with a concussion, is expected to join teammates on the field when camp opens April 6, another NFL source said.

The seventh-round pick from Kentucky — the only tackle general manager Dave Gettleman selected in either of his first two drafts — was not around the team much while healing last year.

Asafo-Adjei has resumed training and is upbeat about beginning his NFL career, the source said. It is possible he could move to guard.