Titans quarterback Marcus Mariota is helped off the field during the first half of Sunday’s blowout loss at Indianapolis. Mariota re-injured his throwing arm and sat out the second half of the game. Coach Mike Vrabel, right, said Monday Mariota suffered a “stinger” unrelated to the previous injury.

-- Ap Photo/Jeff Roberson

In approximately six weeks, the clock will start ticking for the Tennessee Titans and General Manager Jon Robinson.

Barring a run to the playoffs, that’s when the window will open on the future of Marcus Mariota as the Titans quarterback. Mariota is under contract for 2019, but beyond that, who really knows whether the former Heisman Trophy winner is the long-term answer under center in Tennessee.

Nearly four years into his career, we’re still unsure whether it is prudent to pay Mariota and continue to try and build the franchise around him.

On the positive side, Mariota has a playoff win under his belt – something his 2015 draft counterpart Jameis Winston doesn’t have, nor do longtime and highly paid NFL quarterbacks such as Matthew Stafford, Andy Dalton and Alex Smith.

Mariota has also shown enough moxie to direct 11 game-winning drives and nine fourth quarter comebacks during his time under center.

Also, it’s worth remembering the Titans were dreadful when he came aboard as the No 2 overall pick four years ago. Three years later, Mariota had the Titans winning their first postseason game in 14 years.

And then there’s the downside, Mariota’s frequent injuries.

Once again, in Sunday’s 38-10 loss at Indianapolis, Mariota left the game with an injury to his throwing arm. The initial thought was that it might be the same injury Mariota suffered in the season-opener that caused numbness and tingling that lingered for several weeks.

Sunday’s injury, however, was described the day after as a “stinger.” His availability for Monday night against the Texans was to be determined later this week.

Mariota has yet to play a 16-game season. In just three and a-half seasons, there were:

-- Knee sprains – one for each knee – that cost him four games during his rookie season.

-- There was the broken fibula that required surgery late in the 2016 season. That cost him virtually all of the off-season and was to blame for much of his 2017 slump.

-- Mariota’s 2017 effectiveness also was curtailed in midseason by a hamstring injury. It cost him only one game but hampered him in a number of others.

-- This season, Mariota suffered the nerve issue in his throwing hand in the season opener. Depending on the severity of Sunday’s setback, he could miss time again as the season enters the home stretch with the Titans needing to finish strong to have a chance at returning to the playoffs.

The Titans have been here before, having to make a hard decision whether first-round quarterbacks were the franchise’s future. Both Vince Young and Jake Locker made those decisions easier, with the Titans electing to move on without them.

But with Mariota, it won’t be so easy.

Like Young, Mariota has flashed the talent that reflects a special player. But also like Young, he hasn’t been consistent enough to erase all doubts.

And like Locker, injuries have prevented the Titans from getting a full assessment of exactly Mariota can do.

For Mariota and the Titans, it comes down to 2019.

If he plays well next season, stays healthy and the Titans are in contention, Robinson has two options. He can pay Mariota for his efforts or elect to use the franchise tag in lieu of a long-term deal.

If not, then Robinson has to have some sort of alternative plan in place going forward.

What does that entail? Do you spend a high pick on a quarterback as long-term insurance, knowing that those draft choices are needed now to add playmakers on offense and pass rushers on defense?

Everyone in the Titans organization is pulling for Mariota to stay healthy, play well and earn a long-term deal, putting the quarterback question to rest once and for all. That would be a best-case scenario for all involved.

But until that happens, the clock is ticking.