The former West Brom, Fulham and Nottingham Forest midfielder had spent two weeks training with Championship side Rotherham but linked up with Pools earlier this week.
Manager Colin Cooper believes the experience of the 35-year-old would hugely benefit his squad and said: "We've had Jonathan in this week who is another experienced player who can handle a football and has played at the top level for the majority of his career.
"To have him in training is a big bonus for us and I am looking forward to seeing him play and I know that he's looking forward to being involved against Middlesbrough too which is great, so we'll see what happens off the back of that," he told the club's official website.
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