Honestly, all the talks about selling him this summer is too reactive. Look at our midfield, Gini will go, Shaquiri will go, Milner will probably go. If there's one player to be sold, it should be Ox. He's older, has a lower peak, is just as injury-prone, and even offers less than Keita when available, but doesn't get the stick because the expectation with him is low.
What if we sell both? Then we only have Fabinho, Henderson (now turns 31), Thiago (30) and Jones (not starting 11 material yet) as our midfielders. We're not gonna go into the new season with 4 midfielders for 3 slots (2 of them over 30 and have injury problems as well). Do we have the money to buy not 1 but 2 quality midfielders to replace them? No. Then may as well keep the one with more potentials.