He replaced injured Benik Afobe as a late substitute in the Premier League defeat by Chelsea last weekend and could again feature in Bournemouth's squad at Newcastle United on Saturday.
"To be at your peak level after two very serious injuries is an unknown, really. To say when that will be is impossible," Howe told a news conference on Friday.
"I felt it was too big a risk to start him against Chelsea with two games in four days after playing 90 minutes (against Middlesbrough).
"I thought it would be wise to look after him and make sure he's fit, hopefully, for a long time to come."
Bournemouth are second-bottom of the table after 10 league games with two wins, one draw and seven defeats.
The team has managed just six league goals but Howe has refused to blame his close-season signing Jermain Defoe who has struggled for goals.
"Jermain is fine. I think he'll have a big part, a voice in our season," the manager added.
"He's already scored a very important goal (against Brighton), he's had other chances to score and, again, the team has to create and be able to supply him with the chances that he needs."
Bournemouth will travel without Afobe and Junior Stanislas, who also picked up a knock against Chelsea last weekend.
Their opponents ninth-placed Newcastle United are unbeaten at home since their opening day defeat by Tottenham Hotspur.
(Reporting by Hardik Vyas in Bengaluru; Editing by Keith Weir)
