SANTA CLARA, Calif. -- After the San Francisco 49ers boarded their plane following last week's win at the New York Jets, coach Kyle Shanahan and his staff didn't bask in the victory. Instead, they spent at least part of the short flight to White Sulphur Springs, West Virginia, cursing their injury luck and the artificial playing surface at MetLife Stadium.

Despite the dominant 35-13 decision, the Niners were decimated by injuries, most of which were to lower extremities, including season-ending torn ACLs for defensive linemen Nick Bosa and Solomon Thomas. For as difficult as those losses were to swallow, the Niners also faced "a lot of anxiety" that they would return this Sunday to the same field for a Week 3 tilt against the New York Giants.

It has the Niners, who are staying in West Virginia to avoid an additional cross-continental round-trip flight, open to all suggestions. So when a local reporter informed Shanahan the water in the area near The Greenbrier Resort, where the team is staying, is known for its restorative abilities, he didn't hesitate.

"I did not know that about the healing powers of the water," Shanahan said, smiling. "So, I'll stop with the bottled water and get right to that for our players. We could use it right now."

In last week's game, Shanahan said players immediately began discussing how "sticky" the field felt on their cleats. Those conversations continued throughout the game and became louder as six players -- Bosa, Thomas, running backs Raheem Mostert and Tevin Coleman, defensive tackle D.J. Jones and quarterback Jimmy Garoppolo -- suffered injuries.

"I noticed it during pregame, for sure," linebacker Fred Warner said. "The cleats were more -- it seemed like it was a little stickier. The turf was kind of spongy."

On Monday, the Niners expressed concern to the league and the players' association. That resulted in a closer examination of the playing surface, which had previously been certified but had only been played on for one game prior to the 49ers' arrival. Another review of the field during the week by representatives from the NFL, NFLPA, MetLife Stadium, the Giants and Jets, FieldTurf and an independent field inspector offered no change. They verified again that the surface meets all applicable NFL standards and protocols.

But as left tackle Trent Williams explains it, new FieldTurf is trickier to play on because it tends to be thicker when it hasn't been broken in yet.

Most FieldTurf surfaces have multiple layers, including a bottom layer of silica sand, a middle layer with a mixture of sand and cryogenic rubber and a top layer of rubber. As FieldTurf surfaces get worn down, those layers tend to loosen up, which is why players often talk about the "spray" of rubber that kicks up on many older artificial surfaces.

Where those older surfaces might have more "give," the new kind is less forgiving and more likely to make it feel like a cleat is stuck in the field.

"Biomechanical studies have shown that synthetic turf surfaces don't release cleats as easily as natural turf," ESPN injury analyst Stephania Bell said. "Grass allows for the ability to create divots -- which then release the cleats -- under the types of high loads generated during competition. The failure of synthetic surfaces to release cleats in high biomechanical loading situations results in higher torque and shear forces through the lower extremity ... which in turn can result in injury."

An American Journal of Sports Medicine study published in 2019 that focused on synthetic surfaces using infilled turf (a combination of mostly polyethylene fibers mixed with sand and crumb rubber) found play on those surfaces yielded 16% more injuries as compared to natural grass.

Footwear is another important element in the discussion. The league and the players' association have commissioned testing of cleats on synthetic surfaces and shared a list with players and teams naming specific cleats recommended and not recommended for artificial surfaces. It's ultimately up to the players to decide what to wear, though.

According to Shanahan, that's something else the Niners will look at this week as they seek ways to at least have some peace of mind going back to MetLife Stadium.

"I know the players and our equipment guys will be looking at everything possible to help us with that turf," Shanahan said.

After last week's game, 49ers defensive lineman Arik Armstead said there was "a lot of anxiety" about returning to play at the same site seven days after all those injuries. Some teammates echoed that sentiment, though there were others who didn't seem to find the field as problematic.

As Warner pointed out Sunday, the more time spent thinking about something like the playing surface, the more likely a player is to end up playing slower -- and end up hurt. Still, it's hard to flush such memories so quickly.

"I'd be lying to tell you that we're not going to think about it or it's not going to go across your mind," Williams said. "But when you've got a 300-pound lineman in front of you that's trying to put you on your back, I think the surface kind of falls to the back burner. I think for me that's what it's gonna be. With seeing people go down and kind of feeling that turf and kind of knowing where it's at as a playing surface, you do get a little nervous, but I just pray before the game that I'm protected."