INDIANAPOLIS — A second-round pick by the Indianapolis Colts in the 2014 NFL Draft, the team obviously saw tons of potential in Jack Mewhort.

Perhaps not surprisingly, it didn't take long for Mewhort to make an impact along the offensive line, starting in all 30 games in which he played the first two years of his career and quickly earning a reputation as one of the top up-and-coming interior linemen in the league.

But, unfortunately for Mewhort and the Colts, that's when the issues started.

In 2016, he suffered a scary-looking knee injury during the preseason, but was able to return in time for the start of the regular season. He landed back on the injury report by mid-October with a triceps injury, however, and had to miss three games. Then, finally, in the Colts' Week 14 game against the Houston Texans, Mewhort suffered yet another serious knee injury — this time one that shelved him for good, and he was placed on Injured Reserve and underwent surgery.

Heading into training camp in 2017, the team was obviously being careful with Mewhort, giving him plenty of rest days and keeping him out of the final two preseason games. But after trying to battle his way through the first five games of the regular season, the knee issues were just too much, and Mewhort's season ended on IR once again.

And now, with his rookie contract expiring at the end of the 2017 season, Mewhort is set to hit the free agent market for the first time in his career upon the start of the new league year, which begins at 4 p.m. ET on March 14.

The Colts, of course, could decide to try to bring Mewhort back, though they have plenty of other questions along their offensive line to address this offseason.

While Anthony Castonzo (at left tackle) and Jeremy Vujnovich (at left guard) played every snap for the Colts' offensive line in 2017, the three other spots would be filled by a combined 11 other players, mostly due to injuries.

Vujnovich hits the 2018 offseason as an exclusive rights free agent, meaning he has three or fewer tenured years in the NFL and the Colts must make a contract offer by 4 p.m. March 14 to retain him, or he'll become a free agent. Starting center Ryan Kelly, who was only able to play in seven games in 2017 after an injury-plagued year, will be back next year, as will Castonzo, Joe Haeg, Denzelle Good and Le'Raven Clark.

So while the team certainly has some returning pieces up front, general manager Chris Ballard could certainly choose to utilize free agency and/or the draft to add some better competition for a unit that allowed an NFL-high 56 sacks in 2017.2018 Colts Free Agent Watch:* *

• Wide receiver Kamar Aiken
• Inside linebacker Jon Bostic
• Safety Darius Butler
• Cornerback Pierre Desir
• Running back Frank Gore
• Cornerback Rashaan Melvin
• Guard Jack Mewhort
• Running back Christine Michael
• Outside linebacker Barkevious Mingo
• Wide receiver Donte Moncrief
• Center Mike Person
• Quarterback Scott Tolzien
• Kicker Adam Vinatieri
• Tight end Brandon Williams