Summary
Despite starting a number of games for the Spurs in the '19-'20 season, Lyles's minutes went down this season. He struggles on defense, and doesn't hit enough shots at the other end to make up for his defensive deficiencies, which are elevated by the fact that Lyles is strictly a four - not quick enough to guard wings and not big enough to provide rim protection. Lyles did show some growth in attacking off the catch when defenses run him off the three-point line, but still needs improvement in that area to be more than just a spot-up threat.
 
Cap Considerations
Lyles will be an unrestricted free agent with a $7.2 million cap hold and Early Bird rights. Since his cap hold is likely above his market value, his cap hold really isn't that relevant, as the Spurs will either let him walk in order to maximize their cap space, or they will re-sign Lyles and cut into some of their space. Using his Early Bird rights, the Spurs can offer Lyles a starting salary of 5% above the average salary (around $10 million), which should be more than enough. If it's not, the Spurs could always use cap space to re-sign him.
 
Other teams will have multiple ways to sign Lyles as even teams without cap space could possibly use any of the Non-Taxpayer, Taxpayer, or possibly even the Room Mid-Level Exceptions to sign him. It's also a possibility that Lyles could be had for the minimum.