Tony Allen made progress the other day and that was news in and of itself, because it seems that every time he does take a step forward, something else happens to set him back.

Throughout his star-crossed career — and he is the second-longest tenured Celtic behind Paul Pierce, strange as that seems — it has always been something. Knee injuries, coaching changes, rotation shuffles, and then this year an ankle injury and finally thumb surgery, something always seems to get in the way of Allen becoming the player so many people want him to be.

He has seen his friends — Al Jefferson and Delonte West — leave Boston and find fulfillment elsewhere. He has seen a championship team built in their stead while he has continued to search for a role. “Those are my guys,” he said. “Those are my homeboys. But it all changed for the better.”

His thumb still in a cast, Allen has been able to run and he has begun to try to get his conditioning back, but it’s been frustrating. Because of the cast he can’t lift weights with his left arm.

“Not only is it losing your strength, it’s losing your stamina too,” he said the other day before the Orlando game. “It’s unfortunate for me because I can’t strengthen this arm. I can’t do much with this arm with a cast on.”

There are few players on the Celtics roster who can do the kinds of things Allen can do. Before the addition of Stephon Marbury he was really the only member of the second unit who could beat his man off the dribble and get to the basket. Because of his size and quickness he was, and still is, the only member of the second unit who could pick up the league’s best swingmen defensively.

But just as he has a skill set that makes him unique, there is also no player on the Celtics roster who provides the kind of angst that Allen does on occasion. He is capable of the beautiful, the sublime and the blockheaded, and sometimes all three on the same possession. Now in his fifth year in the NBA, Allen is still something of a roller-coaster, the thrilling highs tempered by the slow plateaus.

He had no real role with the Celtics last season, but when the team decided not to re-sign James Posey, the job fell to Allen. Earlier in the year, coach Doc Rivers talked at length about how he had the ability to become a defensive stopper for the second unit. But after an ankle injury cost him 13 games, Rivers reconsidered that notion saying that the reason it hadn’t developed that way rested with the coaches and not the player.

Perhaps too much was expected of Allen. His athleticism, as well as his production, have always hinted at more. Perhaps with more playing time and a defined role, Allen would finally blossom into the kind of Swiss army knife role player every time wishes they had. He could be the backup big guard and slide over to the three when necessary, maybe even handle a little point now and then. It was, and is, a fine notion, but time is simply not on his side this year.

His latest injury is likely to keep him out for at least most of the rest of the regular season, and with Marbury on board there is another option for Rivers where before there was only Allen.

There is much work to be done in the next few weeks for Rivers and the coaching staff. They have to incorporate Mikki Moore into the big man rotation and then figure out where that stands after Kevin Garnett returns. There is also the continuing education and development of Marbury who simply needs time and, most importantly, minutes.

“It will be a while (before things get set),” Rivers said. “It will affect our rotations with the second unit too until we get (Brian) Scalabrine and Tony back. That will take some time.”

In other words, Rivers has to figure out the scenarios with the players he has, not the ones he doesn’t and right now he doesn’t have Tony Allen.

Marbury and Eddie House have become the de-facto backup backcourt, and Rivers has not wanted to define them too much, saying that the point guard is the one who winds up with the ball in his hands. He also said last week that there could be a scenario when Marbury spells Ray Allen at the two-guard and joins Rajon Rondo in the lineup, with Rondo playing the point and Marbury playing off the ball.

As a shooter of unparalleled ability, House will have a role, but now it is Marbury who can become the utility guy. Where that leaves Allen is anyone’s guess.

“I want to come back and contribute any way I can contribute,” Tony Allen. “That’s all I’m looking forward to. I’m watching these games closely and looking to see where I can fit in.”

Tony Allen has been written off and buried so many times in the past that it would be unwise to do so again. He may yet prove he can be that versatile option off a bench that badly needs some diversity, but for now he can only watch and wait.

Paul Flannery is a regular contributor for WEEI.com.