The Toffees know what they'll be getting from Tarkowski.
He's a tried-and-tested top-flight performer who has ambitions of making England's World Cup squad at the end of the year.
Lampard's spoken about making Everton more robust and that's a quality Tarkowski will indeed bring. In the past four seasons, he's missed just eight games.
All in all, Everton will be delighted amid reported interest from Aston Villa and Newcastle United. He strengths their options.
Settling the defence
And Lampard will know what his next priority is - to settle down the Blues' defence during pre-season.
In total, Everton used 23 different combinations (including wing-back systems) throughout the 2021-22 league campaign.
It's scant surprise, then, that the Toffees' rearguard was far too permeable, with 66 goals conceded and relegation narrowly avoided.
Only Norwich City (84), Leeds United (79, Watford (77) and Southampton (67) shipped more.
The persistent chopping and changing undoubtedly contributed to the Toffees' defensive frailties.
It may be cliche but there's something to be said for an established back four.
The defence is the bedrock to any side with designs on being successful. Relationships and rapports are imperative.
Lampard will be acutely aware of this. He'll have ideas on who he wants in his rearguard week in, week out.
In truth, it's why large sections of supporters would be happy to offload Yerry Mina.
The Colombia international is a high-class performer and arguably the best defender at Goodison.
However, Mina was available for a paucity of games last season was sparse. He made just 13 Premier League appearances because of various muscle injuries.
Since arriving from Barcelona in 2018, he's averaged 20 league outings per campaign.
The 27-year-old has a year left on his contract and is said to be one of the club's higher earners.
From a business point, removing Mina from the wage bill and netting a fee would be prudent.
He has been linked with Marseille.
Ben Godfrey's opening to last term was severely disrupted. He contracted Covid-19 days before the curtain-raiser against Southampton, causing him to miss four games - and then took a protracted period to get up to speed.
The England international also had his injury problems after Lampard took the hot seat in January. Godfrey firstly suffered a hamstring issue in February then a thigh complaint while warming up before the Merseyside derby against Liverpool in April.
But plenty would concur that the ex-Norwich defender should be earmarked as Tarkowski's chief partner ahead of Michael Keane and Mason Holgate.
After all, Godfrey was Everton's Young Player of the Season in 2020-21 and named in the Three Lions' provisional squad ahead of the Euros.
Vitalii Mykolenko expectedly took a period to bed in after his £19 million arrival from Dynamo Kyiv in January. Russia's invasion of his homeland Ukraine also set him back in terms of acclimatising.
But he would start 10 successive games to help the Blues secure their top-flight status. During that period, Mykolenko made hurtling progress and swiftly won over any doubters.
The 23-year-old now has the chance to work with one of the Premier League's greatest-ever left-backs in Ashley Cole over pre-season.
He has burgeoning potential, while Niels Nkounkou will return after his loan spell at Standard Liege.
The right-hand side is the intriguing position. Seamus Coleman was eulogised by Lampard in the dressing room after the dramatic defeat of Crystal Palace which saw Everton safe.
The captain commands the utmost respect of his manager and team-mates. His experience and nous are priceless.
Coleman turns 34 in October, though, and Lampard has to weigh up whether to stick with him or pass the baton to Nathan Patterson.
The Scotland international made just one appearance after signing from Rangers in January and his campaign was curtailed in April when forced to undergo ankle surgery.
That, of course, is if Lampard wants to revert to a flat back four.
Everton found success playing a wing-back system in the business end of the campaign, with the relentless Alex Iwobi down the right flank.
Regardless of the formation Lampard prefers, continuity will prove paramount.