England will consider adding one of their three reserve spinners to their main squad ahead of the first Test against Sri Lanka on January 14, after head coach Chris Silverwood ruled Moeen Ali out of contention.

Ali has been self-isolating after returning a positive Covid-19 test on arrival in Sri Lanka, with his quarantine period ending on January 13, the day before the first Test. As a result, England may look to one of the three spin bowlers who travelled with the squad as reserves - Mason Crane, Matt Parkinson and Amar Virdi - to keep their options open. Parkinson and Virdi are both uncapped, while Crane's only Test came in the Sydney dead-rubber at the end of the 2017-18 Ashes.

Silverwood expects to get a first look at the pitch at Galle - where both Tests will be played - when England train on Monday afternoon. Sri Lanka coach Mickey Arthur told the Guardian last week that he is anticipating "typical Sri Lankan conditions", and if the surface looks particularly spin-friendly, England may look to field three frontline spinners as they did in their 3-0 series win in 2018.

"They're in the group, they're here, so they're available," Silverwood said. "We'll have a look tomorrow, and then we'll make a decision on where we go. We travel with such a large group now, so should any eventuality come up then we've got it covered.

"We've got [Dom] Bess and [Jack] Leach in the front line and Rooty [Joe Root] can be effective as a spinner, but we've not seen the pitch down in Galle yet. We'll see that tomorrow and conversations will go from there. We can play plenty of spin if required to."

Silverwood also confirmed that Ali was unavailable for selection in the first Test. Silverwood said that Ali was "feeling OK in himself from a physical point of view," but his involvement in the second Test of the series is in doubt, given he will have spent two weeks in hotel-room isolation before he is able to train, and the short turnaround between Tests.

"If it's not swinging, you can try and use the pace to try and force an issue. Having that up your sleeve when you are in a Test match is always a very nice thing to have for a captain - to be able to turn to somebody that can genuinely bowl fast"
Silverwood hinted that England may pick either Olly Stone or Mark Wood

Whether England choose a third spinner or not, there will be a significant burden placed on Bess and Leach throughout the next two months, with a four-match series in India following immediately after the Sri Lanka tour. Bess played all six home Tests last summer, taking eight wickets at 55.50, but Leach has managed only two first-class appearances in the last 12 months after spending most of the home season on the sidelines in the England bubble.

"He's looked good on tour so far," Silverwood said. "He's worked hard at home before we came out here and he's prepped very well. When we were in South Africa, the red-ball squad were training hard in the marquee at Loughborough. It's just a case of making sure he feels confident on Thursday in that final XI and that he goes out and performs.

"I imagine there's going to be a few nerves around because he hasn't played for a while but he won't be the only one - the team in general hasn't played a Test match for a long time. He'll be fine. [We'll] get him into the attack and let him go."

Meanwhile, Silverwood hinted that Sam Curran could be included in the side for the first Test, and that England are likely to avoid pairing James Anderson with Stuart Broad as they place emphasis on "variety" in their attack.

If England opt to play two frontline spinners, Curran's main rival for the No. 7 spot will be Chris Woakes, who re-joined the squad on Saturday after self-isolation as a close contact of Ali's. With Jofra Archer rested for this series, England may instead turn to Olly Stone or Mark Wood, if they decide that they need a 90mph/145kph bowler in their XI.

"The timelines are tight for Chris," Silverwood said. "He will train tomorrow [Monday] and that will be his first training session, really. We've got to be realistic in our expectations that people won't play in every Test match and we'll be resting and rotating players and looking after them.

"Having the option of that extra pace in your armoury so that if it is flat, you have something to go to. If it's not swinging, you can try and use the pace to try and force an issue. Having that up your sleeve when you are in a Test match is always a very nice thing to have for a captain - to be able to turn to somebody that can genuinely bowl fast.

"You're looking at who can swing it, who can contain, left-arm, right-arm. You want different options in there so that at any given point, the captain… has as many options up his sleeve [as possible]. Not only have we got a wealth of experience in Jimmy and Broady, we have people who do different things as well."

Matt Roller is an assistant editor at ESPNcricinfo. He tweets at @mroller98