Diop has been out of action since December after picking up a knee injury in the defeat to Arsenal.
The former Fulham man has returned to training and he is hoping to prove his fitness ahead of the big kick-off in August by featuring in some of Pompey's pre-season friendlies.
"I can't wait to get out on the pitch again, so I'm looking forward to the friendly matches," Diop told the club's official website.
"I haven't played for a long time, so I need these games to get myself ready for the start of the season. Although I was doing some light training by myself at the end of last season, it's much better to be with the rest of the squad.
"I only played for half the season last year and was out injured for the other half, so I want to play more games this season. It was frustrating to be injured last year and to have to watch when I wanted to be out on the pitch.
"But now I'm just looking forward and concentrating on working hard in training to get myself back into the team. Hopefully I can do that and help Pompey to have a successful season in the Premier League."