ORLANDO, Fla. -- The Detroit Lions traded their fifth-round pick to Jacksonville for a receiver who isn't even in the league anymore, let alone wearing Honolulu blue. And what did they get out of Mike Thomas?

Five catches, 28 yards, one touchdown.

Some trades work out, and others don't, regardless of sport or team. But that's an anemic return on investment, and general manager Martin Mayhew isn't making excuses for it.

'I'm just being honest: That's on me," he said last week. "It's my job. I'm in charge of acquiring players, right? We got a player, he didn't do anything for us, I can't blame somebody else for that."

Thomas had caught at least 44 passes in each of his three seasons with the Jaguars, and Mayhew was enticed by his flexibility. He envisioned the speedster as playing inside or outside in then-coordinator Scott Linehan's scheme.

So Mayhew traded for him on Oct. 20, 2012. And Thomas didn't really fit in anywhere.

He played only nine games for the Lions that season, and couldn't even make last year's roster despite the Lions' depth issues at the position. He was cut Aug. 19, after less than a year in Detroit.

What went so wrong?

Mayhew said he should have better defined what Thomas' role would be before making the move.

"It would have been better to figure out exactly what his role in the offense was, and exactly how we were going to utilize him, and exactly what we were going to do with him," Mayhew said. "The thing that I think hindered that, at least from my standpoint -- it's on me, really -- was his versatility. He can do so many different things, I just figured, 'We'll figure out what to do with him.' And we never really figured out what to do with him.

"So that was on me for not, I think on the front end, making sure I had an understanding of what he was going to do in our offense. Was he going to be a slot guy? Was he going to be an outside guy? What his role was, really. And rather than do that, because he was so versatile, I saw him in the backfield, I saw him in the slot, I saw him outside, I saw him special teams, I figured we would find something he could do. And we just never found anything for him."

Mayhew said Thomas preferred to play in the slot, while the Lions wanted him outside.

"He wanted to be in there and he wasn't there," Mayhew said. "All those things come into play, but ultimately it's my job when we go and acquire somebody, to know what we're acquiring that guy for, and that's why we have personnel meetings, that's why we do all the draft meetings.

"At the end of the meeting, one thing we have on our report is 'role for the Lions.' So the coaches say what the guy's role is. This guy is a nickel cornerback, or he's a safety, or he's a strong safety, or he's a slot receiver, or he's the third-down back. Whatever it is, and then we know, 'hey, there's a role for this guy here.' Where if there's no real role for him or it doesn't sound very attractive, you go, 'This guy is a de-activated fifth offensive tackle in case somebody gets hurt, well, we don't draft that guy.' So I think ultimately the Mike Thomas thing is on me for not knowing exactly what his role is going to be."

The Lions did receive two fourth-round compensatory picks from the league last month, which gives them six of the first 136 selections in the draft and eight overall.

That takes out some of the sting of trading away a pick for basically nothing.