NASHVILLE, Tenn. — Tennessee Titans left tackle Taylor Lewan announced that he tested positive for the banned substance ostarine and is facing a suspension. Here are some answers to questions about the situation as the Titans head toward training camp.

What is ostarine?

Ostarine is a selective androgen receptor module (SARM) that has effects similar to those of anabolic steroids. According to the U.S. Anti-Doping Agency (USADA), it is not approved for human use or consumption in the U.S. Ostarine is not available as a prescription medication.

According to the USADA website, “some dietary supplement manufacturers illegally put SARMs like ostarine in their products. … Moreover, they may omit ostarine from the label entirely, or use misleading names to confuse consumers.”

The USADA produces a list of high-risk supplements that contain products that fall under the scope of banned substances outlined in the World Doping Agency code.

How does the appeals process work?

A source told ESPN’s Adam Schefter that Lewan’s A sample tested positive this summer, but the results of his B sample had not come back yet. If the samples match, Lewan will face a four-game suspension, and he will appeal.

According to the NFL/NFLPA’s joint statement outlining changes to the league’s drug policy in 2014:

“Appeals of positive tests in both the substance abuse and performance-enhancing drug programs (including HGH) will be heard by third-party arbitrators jointly selected and retained by the NFL and NFLPA.”

These third-party arbitrators are not affiliated with the NFL, NFLPA or NFL teams. The NFL’s policy on performance-enhancing drugs states the following regarding the timeline for appeals to be heard:

“Appeals will automatically be assigned to the arbitrator assigned to cover the fourth Tuesday following the date on which the player is notified of discipline. During the off-season, the Notice Arbitrator shall assign appeals on a rotating basis such that a hearing may be scheduled within thirty (30) days of the issuance of the notice of discipline.”

A player can challenge the way the sample was collected. Former Seahawks cornerback Richard Sherman won an appeal in 2012 when an arbitrator ruled that “improper practices” were used in the process of collecting his positive sample.

If Lewan is suspended, who will start in his place?

The left side of the offensive line was set in stone with Lewan and newly acquired left guard Rodger Saffold lining up next to him. Now Dennis Kelly becomes the primary option to replace Lewan, but he was projected to battle with Jack Conklin for the right tackle position. Lewan suffered a concussion in last year’s season opener that kept him out of the Titans’ Week 2 game against the Texans. Kevin Pamphile started at left tackle in his place. Pamphile is currently the favorite to start at right guard but is expected to compete with rookie Nate Davis for the spot.

Here are two possibilities for the starting offensive line:

LT Dennis Kelly | LG Rodger Saffold | Center Ben Jones | RG Kevin Pamphile | RT Jack Conklin

LT Kevin Pamphile | LG Rodger Saffold | Center Ben Jones | RG Nate Davis | RT Dennis Kelly

What would the Titans lose in Lewan?

The Titans would be losing one of their best players. According to ESPN Stats & Info, Lewan had an 85.8 Pass Block Win Rate last season. That placed him 20th among all offensive linemen with at least 300 blocks and 10th among offensive tackles. As a unit, the Titans’ offensive line ranked 25th (43.8%) in that department. That’s bad news for a team that is looking to keep Marcus Mariota healthy for a 16-game schedule, which he hasn’t been able to do yet in his career.

As for the rushing attack, losing Lewan is bad news for Derrick Henry, who’s entering a contract year. Last year, Henry averaged 5.84 yards per carry when running to the left — Lewan’s side. On carries that strictly went outside of the left tackle, Henry’s average per carry was 5.1 yards.

Lewan was also a player Mike Vrabel leaned on for leadership on the offense. When the Titans needed a spark in practice, Lewan was tasked with providing it.

What does this mean for the offense in the first four games?

The Titans open the schedule with a road game at Cleveland, followed by the home opener against the Colts and road games against the Jaguars and Falcons. Not having Lewan to go against pass-rushers such as the Browns’ Myles Garrett and the Jaguars’ Yannick Ngakoue will disrupt the pass protection. Lewan is typically asked to take on the opposing team’s top pass-rusher.

Now the Titans will have to slide protection to the left side whenever they face premier players such as Garrett and Ngakoue. They’ll have to find ways to buy time for Mariota to look for receivers down the field on longer developing routes. That isn’t an easy task without their Pro Bowl left tackle. The offense could rely more heavily on the quick passing game, with Adam Humphries working the slot and quick-hitting routes by tight end Delanie Walker.