Damian Lillard’s near-halfcourt buzzer beater to win Game 5 not only sent the Portland Trail Blazers into the Western Conference semifinals, but it sent the Oklahoma City Thunder to yet another early playoff exit since the team lost Kevin Durant in free agency.

Despite being the No. 6 seed, many believed that OKC was the favorite in their first-round series, but they were unable to find a rhythm and close games throughout the series. In Game 5, OKC led by 15 points with about six minutes to play, but they folded down the stretch and gave the series away.

While the issue likely isn’t just one piece of the Thunder, Paul Pierce believes that much of their playoff struggles are due to head coach Billy Donovan, rather than pinning the blame on Russell Westbrook or Paul George, who Paul called easy targets.

“It would be easy to attack Russ. It would be easy to attack Paul George, but I put a lot of this on Billy Donovan. This is the third year in a row this team (has been beaten) in the first round. It’s not like they didn’t have the talent. They haven’t lived up to expectations in the regular season,” Pierce said. “I think there are a lot of flaws in their offensive and defensive systems that they can clean up.”

Amin Elhassan agreed that Donovan deserves part of the blame, but he also attributed some of their shortcomings to injuries and the way Sam Presti has built the roster, which doesn’t feature enough three-point shooter around Russell Westrbook. Amin suggested, however that Westbrook’s desire to “win” his positional matchup, against Damian Lillard in this series, has been the ultimate cause of OKC’s failure in recent playoff series.

Looking ahead to next season, the Thunder have the second-highest payroll in the league despite needing to potentially overhaul their roster to acquire more shooter and playmakers. While there are potential sleepers they can find that will contribute in a big way, it will be difficult to make any major changes to the roster.

“There’s not much they can do,” Pierce said. “It’s infrastructure. They’ve got the talent.”